South Australia's auction rules: bidders, vendor bids and the Form 1

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Kooky

Builder of Shaka, the payment router that pays every agent their commission on closing date.

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A residential auction in South Australia looks informal from the footpath: a crowd on a front lawn, an auctioneer, a few raised cards. Behind it sits a detailed code. The Land and Business (Sale and Conveyancing) Act 1994 gives a whole part, Part 4A, to auctions, and the regulations made under it add a set of standard conditions that apply to every agent-run auction of residential land in the state, whatever the agency's own paperwork says.

The question this guide answers is a practical one: what does South Australian law require before, during and after the fall of the hammer, and what does each rule mean for the bidder, the vendor and the agent? It covers the reserve and the limit placed on it, the documents that must be on display, bidder registration, the standard conditions, vendor bids, dummy bidding and the other offences, the contract and deposit, a property that is passed in, and the place of cooling-off and the Form 1. Everything below is South Australian law and guidance; other states and territories have their own rules.

Land and Business (Sale and Conveyancing) Act 1994 (SA), sections 24O, 24J and 24N, version dated 15 January 2026.

Where the rules come from

Three layers of material set the rules. The first is the Act itself, in the version dated 15 January 2026 on the South Australian legislation register. Part 2 deals with cooling-off and the vendor's statement, and Part 4A, sections 24I to 24P, deals with auctions. The second layer is the Land and Business (Sale and Conveyancing) Regulations 2025, which commenced on 1 September 2025 and repealed the 2010 regulations. The third is the guidance of Consumer and Business Services, the state regulator known as CBS, which registers agents and auctioneers and publishes the bidders' guide that every registered bidder must be handed.

Several of the auction provisions apply only to "residential land", so the definition matters. Under section 3 of the Act the term covers land with one or two places of residence and no other improvements, vacant land on which a residence may lawfully be built, and certain community and strata lots. It leaves out land used wholly for non-residential purposes and land of more than 2.5 hectares, unless another area is prescribed. Some provisions, such as the ban on dummy bidding and the collusion offences, are written for auctions of land or a business generally and are not confined to homes.

Only a registered auctioneer can sell at auction, according to the South Australian Government's guidance for sellers, last updated on 9 June 2026. Auctioneers carry a registration card issued by CBS.

The reserve and the 110 per cent ceiling

The reserve is the lowest price the vendor will accept. The state's seller guidance says it must be set in writing before the auction and is not shared with bidders, and the CBS factsheet for sellers adds that the written reserve is what authorises a sale to the highest bidder at or above that figure. The agent must keep written records of it.

The reserve is tied to an earlier document. Before an agent can act, the vendor signs a sales agency agreement. Section 20 of the Act requires that agreement to state the agent's estimate of the selling price and the price the vendor seeks or will accept, each as a single figure and not a range. Section 24J then provides that the reserve must not, at any time before or during the auction, be set above 110 per cent of the price the vendor sought in that agreement. The seller guidance adds a second lock: where the property is being sold by auction, the acceptable selling price in the agreement cannot be increased.

A worked example shows the effect. Assume a vendor signs a sales agency agreement naming A$800,000 as the acceptable selling price. The highest reserve the Act allows is 110 per cent of that figure: A$800,000 multiplied by 1.1, or A$880,000. A reserve of A$880,000 is within the limit; a reserve of A$900,000 is not, on the morning of the auction or halfway through it.

The same agreement also governs advertising. The CBS factsheet says an agent must not promote a price below the higher of the agent's own estimate and the vendor's acceptable price. The agreement itself runs for a maximum of 90 days, according to the same factsheet.

The documents that must be on display

Four documents have to be available to the public before a residential auction starts, and each has its own timetable.

The first is the vendor's statement, known as the Form 1. It is the form in Schedule 1 of the 2025 Regulations, made under section 7 of the Act, and under that section it sets out the buyer's cooling-off rights and the mortgages, charges and prescribed encumbrances affecting the land. In a private sale the vendor must serve it at least 10 clear days before settlement. An auction works differently. Section 11 of the Act requires the statement to be available for public perusal at the office of the agent or auctioneer for at least 3 consecutive business days immediately before the auction, and at the place of the auction for at least 30 minutes before it starts.

The second is the buyer's information notice, the Form R3. The state's buyer guidance, last updated on 18 March 2026, says it must be available on the same timetable, 3 business days at the office and 30 minutes at the site, and should be attached to the Form 1.

The third is the standard conditions of auction. Section 24J requires the responsible agent to make them available for public perusal at the venue for at least 30 minutes before the auction is due to start, and requires the auctioneer to announce, immediately before the start, that they apply.

The fourth is the collusive practices notice. Regulation 28 of the 2025 Regulations requires it to follow the form in Schedule 7, to be in type no smaller than 12 point, and to be available at the place of the auction for at least 30 minutes before the auction is due to commence. An auctioneer who sells without that notice having been given faces a maximum penalty of A$5,000 under section 24L of the Act.

Registering to bid

Nobody can bid on residential land in South Australia without being on the bidders register. Section 24K of the Act forbids the auctioneer from taking a bid unless the bidder is in the register, the auctioneer holds the register, and the bidder displays the unique identifier recorded against their name. The maximum penalty for the auctioneer is A$10,000.

The CBS bidders' guide, a prescribed document titled Form 4 and dated January 2025, explains the process from the bidder's side. Anyone who intends to bid must register, and registering creates no obligation to bid. Registration can be done before the day, for example at an inspection, or at the auction. Where two people are buying together, only one needs to register, and only that person may then bid.

Regulation 27 sets out what the agent writes down: the full name and address of each intending bidder, a general description of the proof of identity produced, and the agent's signature confirming that the proof was sighted. The proof can be a driver's licence, a passport, a credit or debit card, a gas, electricity or telephone account, or a similar document or card issued to the person. The bidders' guide adds that the document does not have to be left with the agent and does not have to be copied.

Bidding for someone else carries extra steps. The regulation requires the bidder to give the agent a written authority signed by the other person and to produce proof of that person's identity, which for a company is its certificate of incorporation. The register then records the principal's full name and address and a statement that the bidder is acting on their behalf.

Once registered, a bidder receives the bidders' guide and an identifier, which the guide says may be a number, a letter, a colour or another feature, and which must be shown with every bid. Giving false information for the register is an offence, and so is misusing it: section 24J sets a maximum penalty of A$10,000 for knowingly entering false details and the same for disclosing or using information from the record without authority. The guide says register information may be disclosed only when an authorised person requires it under the Fair Trading Act 1987.

On latecomers, the Act and the guide fit together. Section 24J provides that if a bid is to be allowed from a person who was not registered beforehand, the auction must be interrupted and the person's details entered in the bidders register. The bidders' guide tells bidders that an agent may pause the auction to register a late arrival but is not obliged to.

What the standard conditions say

The standard conditions are prescribed by regulation 26 and set out in Schedule 6 of the 2025 Regulations. Under section 24I of the Act they are binding on three relationships at once: between vendor and purchaser, between vendor and auctioneer, and between the bidders and the auctioneer.

The bidders' guide summarises them. Bids may be made in person or through a proxy or representative. The reserve is the amount recorded in the auction record. Only registered bidders may bid, and a bid is accepted only when the bidder shows the identifier and the auctioneer announces it aloud.

The auctioneer keeps wide control of the floor. The size of each bidding increment is at the auctioneer's discretion, and the auctioneer may refuse a bid that is not in the vendor's best interests without giving a reason.

The result is fixed by a simple rule: the highest bid at or above the reserve wins, and that bid becomes the purchase price. No bid is accepted after the hammer falls.

Vendor bids: three at most, announced each time

South Australia does not ban bidding on the vendor's behalf outright: it channels it through the auctioneer and caps it. Section 24O of the Act allows the auctioneer to make up to 3 bids for the vendor at an auction of residential land, where four conditions are met: the conditions of auction permit it, the auctioneer announces before bidding starts that such bids are permitted, each bid is announced as a vendor bid when it is made, and each bid is below the reserve. For land that is not residential, or a business, the Act allows one or more vendor bids on the same terms.

Two consequences follow. A vendor bid can never be the bid that buys the property, because it sits below the reserve. And the agent's auction record must show vendor bids as such, so the count can be checked afterwards.

Take the earlier worked example, with a reserve of A$880,000. If genuine bidding stalls at A$820,000, the auctioneer may announce a vendor bid of, say, A$840,000. That is one of three. A vendor bid of A$880,000 or more would not be below the reserve, as the Act requires.

There is also a rule for the days after an unsuccessful auction. Under section 24P, where a property is passed in and the last bid was a vendor bid, any marketing statement that quotes that amount must also say the bid was made for the vendor. The maximum penalty is A$10,000, and it reaches people who pass the figure on and publishers of auction results as well as the agent.

Dummy bidding, collusion and disruption

Outside the three announced vendor bids, any bid for the vendor is a dummy bid. Section 24N of the Act says a vendor must not bid at an auction of their own land or business, nobody may bid knowing the bid is made on the vendor's behalf, and nobody may procure another person to do so. A bid can be found to have been made on the vendor's behalf even where the vendor did not ask for it or know of it. For this section "vendor" includes a mortgagee or other holder of a security interest.

The auctioneer is bound twice over: by a ban on taking a bid known to come from or for the vendor, and by a ban on purporting to take a bid when no bid is being made. Each breach carries a maximum penalty of A$20,000.

Bidders have duties too. Section 24L makes it an offence to induce others to stay out of the bidding or otherwise limit competition, and an offence to act on such an arrangement. Section 24M forbids a bidder from knowingly preventing a rival from bidding freely or harassing a rival, and forbids anyone from acting with the intention of preventing an auction, seriously disrupting it or having it cancelled.

Two qualifications apply. Section 37B gives a general defence to a Part 4A offence where the conduct was not intentional and reasonable care was taken. And the Act states, for the record-keeping and registration sections, that a contravention does not affect the validity of a bid or of the contract.

The hammer falls: contract and deposit

A sale at auction is unconditional. The state's buyer guidance says a contract made at auction cannot be made subject to finance, so a bidder's finance has to be settled before auction day, not after it.

Under the standard conditions, a contract in the form displayed at the auction must be signed immediately after the hammer falls and the deposit paid at that time, unless something else has been agreed in writing. The conditions also give the auctioneer an irrevocable authority, once the hammer has fallen, to sign the contract for the purchaser, for the vendor or for both.

No source read for this guide fixes the deposit by law. The buyer guidance says auction conditions are generally a 10 per cent deposit and a 30-day settlement, and that the deposit is usually a minimum of 10 per cent of the bid price. The bidders' guide puts it as usually around 10 per cent and says a lower amount may be negotiated with the agent before the auction. As a worked example on those general terms, a winning bid of A$900,000 with a 10 per cent deposit means A$90,000 payable on the day, with the remaining A$810,000 due at settlement.

When the property is passed in

If bidding stops below the reserve, the buyer guidance gives the vendor three courses: not to sell, to negotiate with any bidder, or to place the home on the open market. The CBS factsheet for sellers adds a fourth that can be used while the auction is still running, which is to lower the reserve to the level of the highest bid.

Negotiation after a pass-in has its own cooling-off rule. Section 5 of the Act removes cooling-off where land is passed in at auction and a bidder contracts on the same day. The bidders' guide spells out the deadline: a person who bid at the auction and signs a contract before midnight on the auction day, after further negotiation with the vendor, has no cooling-off period.

The auction record follows the negotiation as well. Regulation 27 requires the agent to record the full name and address of any bidder the auctioneer negotiates with on the same day, the amounts offered, and the sale amount if a sale results that day.

Cooling-off and the Form 1

In an ordinary private sale of land in South Australia the buyer has a cooling-off right. Section 5 of the Act allows the purchaser to rescind by written notice before the end of the second clear business day after the contract is made, or after the Form 1 is served if that happens later. The Legal Services Commission of South Australia explains in its Law Handbook that the day of service is not counted and that weekends and public holidays are not counted. As a worked example, assuming no public holiday in the week: where the Form 1 was served first and the contract is signed on a Monday, the period ends at the close of Wednesday; where it is signed on a Friday, it ends at the close of the following Tuesday. On cooling off, the buyer is refunded what was paid, except that under the Act the vendor may keep a deposit of up to A$100.

An offer accepted before auction day is a private contract, so cooling-off applies. The buyer guidance says the right can be waived only where an independent legal practitioner signs a prescribed form confirming that the buyer was advised about the right being given up; in the 2025 Regulations that is Form 3, with the practitioner's certificate in Part A and the buyer's instrument of waiver in Part B. The Law Handbook notes that vendors or agents usually ask for a waiver in exactly this situation, an offer made on a property already scheduled for auction.

With no cooling-off at auction, the 3 business days of public display are when a bidder can read the Form 1 before becoming bound. Where an agent acts for the vendor, the agent must make the prescribed inquiries and sign a certificate; Part D of the Form 1 is that certificate.

A defective Form 1 has consequences that survive the hammer. Under section 15 of the Act, a purchaser who was not given the statement, or was given one that was not certified or was defective, may apply to a court. If the court is satisfied that the purchaser was prejudiced, it may avoid the contract and order restitution, award damages, or make other orders, and damages can be awarded against the vendor and against the agent. Section 16 gives defences, among them that the failure was unintentional and not negligent, or that it arose from reliance on information supplied in answer to a required inquiry. Whether a particular error meets that test depends on the case. Separately, contravening a provision of Part 2 carries a maximum penalty of A$10,000 under section 14.

The record the agent keeps

Every residential auction leaves a file behind. Section 24J requires the responsible agent to make a written auction record before the auction starts, and regulation 27 lists what it opens with: the street address of the land or a description that identifies it, the full names of the vendor, the responsible agent and the auctioneer, the date and time of the auction, and the bidders register. The reserve, and any change made to it before the auction, must already be in the record when bidding begins.

During the auction the record grows in real time. The Act requires each bid to be entered with its amount and the bidder's identifier, vendor bids to be entered as vendor bids, any change to the reserve to be noted, and every entry to be made immediately the event occurs. If the property sells, the purchaser's full name and address and the sale amount are added.

Section 37A requires the agent to keep the record at a place of business in South Australia for 5 years, on paper or electronically, and allows an authorised officer to inspect it. Failure to keep it carries a maximum penalty of A$5,000. It shows what the reserve was at each moment, how many vendor bids were made, and which identifier made every other bid.

One point remains open on the sources read. The standard conditions are described here from the CBS bidders' guide dated January 2025, which was issued before the 2025 Regulations commenced on 1 September 2025. The current wording is the one in Schedule 6 of those regulations, as displayed at the auction.

Kooky, from Shaka

Kooky edits Agents Estate and builds Shaka, the payment router he made for real estate professionals. One payment comes in, and every agent, agency and party in the deal receives their signed share on closing date.

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