Auction rules by state

Why the rules differ at all

Property auctions are regulated by the states, not the Commonwealth. Each has its own legislation, its own consumer regulator and its own history of reform, usually driven by whatever scandal happened locally. Dummy bidding crackdowns arrived at different times and in different shapes across the country.

The result is that an auction in Adelaide and an auction in Perth are the same event with materially different rules, and almost nobody selling for the second time in a different state realises it.

Vendors assume the rules they learned last time still apply. Buyers assume what they saw on a Melbourne auction show applies in Brisbane. Both are wrong often enough to matter.

Ben Williams, Founder

The comparison table

Five states, the ones Unreserved is licensed in. Where a cell says to check locally, that is a genuine gap rather than a formatting choice, and the reason is explained further down.

Bidder registration

Three of the five require you to register before you can bid. Two do not. This is the single most visible difference on the day, and the one that most often catches an interstate buyer out.

Vendor bids

A vendor bid is made by the auctioneer on the seller’s behalf to move bidding toward the reserve. Legal in every state when announced, and the permitted number varies more than any other rule on this page.

Queensland and Western Australia tie the count to the reserve rather than to a number: a vendor bid at or above the reserve becomes an illegal false bid, so the ceiling is the reserve itself. Western Australia additionally requires the intended number to appear in the conditions of sale.

The mechanic, the announcement requirements and how buyers read a vendor bid are covered in full in vendor bids explained.

Reserve price rules

Two states clearly require the reserve to be recorded in writing before the auction. New South Wales makes it a prescribed condition of sale, and Queensland requires the seller to put it in writing with the agent beforehand. Western Australia’s regulator describes the reserve as set before the auction and kept confidential from bidders.

Victoria is the state to watch. A Bill before the Victorian Parliament would require the reserve to be confirmed in writing as a single dollar amount, published at least seven days before the auction, and frozen once published. It passed the Legislative Assembly on 30 July 2026 and is with the Legislative Council. It is not law yet, and the proposed commencement is 1 October 2026.

How the number should actually be arrived at, in every state, is in how to set your reserve price.

Cooling-off, before during and after

One rule is national: there is no cooling-off period for a buyer who buys under the hammer at a public auction, anywhere in Australia. Everything either side of the hammer is state-specific, and this is where people get caught.

The Victoria and South Australia positions on pre-auction offers are opposites, which is worth knowing if you are weighing an early offer. A Victorian offer accepted inside three clear business days of the auction carries no cooling-off. A South Australian offer accepted before the auction does carry it, unless the buyer waives the right.

What to do in those hours, and the trade-off between an unconditional buyer and a better decision, is in passed in at auction.

Deposits

The deposit is usually set in the conditions of sale and announced before bidding starts, rather than fixed by statute. Ten per cent is the common convention, but it is negotiable in most states and the announced figure is what binds.

• VIC: payable on signing, and the contract cannot be made subject to conditions. A part deposit with the balance on a set date can be negotiated.
• WA: the regulator describes about 10 per cent at the close of the auction.
• QLD: set in the conditions of sale and announced before bidding, payable by personal cheque, bank cheque or deposit bond.
• SA: the law permits only a token deposit of up to $100 on signing, which is a different thing from the deposit payable at settlement and catches people out.

Late bids and disputed bids

Two states address this expressly in their rules. Victoria requires the auctioneer to announce before bidding that bids will not be accepted after the fall of the hammer, and New South Wales prohibits it as a prescribed condition, with the auctioneer named as the sole arbiter of any dispute about a bid.

Queensland’s standard conditions of sale give the auctioneer the same discretion, including the power to reopen bidding at the last accepted bid. That comes from published conditions of sale rather than from the regulator, so treat it as normal auction practice rather than as statute.

What this page does not claim

Several cells above say to check locally. That is deliberate, and it is worth being explicit about why rather than quietly leaving them blank.

• Western Australia: late bids, disputed bids and whether the reserve must be in writing. Consumer Protection WA’s published guidance defers these to the individual Authority to Auction contract rather than stating a rule.
• Victoria and South Australia: whether the reserve must be recorded in writing. Not established from the regulators’ published guidance.
• Victoria: bidder registration. No requirement appears in the regulator’s guidance and secondary sources agree there is none, but absence of a published rule is not the same as confirmation.

We would rather publish a table with three honest gaps than one with three confident guesses. If you need certainty on any of those points for a live campaign, your conveyancer or the state regulator can answer it in a phone call.

Common questions

Are auction rules the same in every Australian state?

No, and the differences are not cosmetic. Bidder registration is required in New South Wales, Queensland and South Australia but not in Victoria or Western Australia. The number of permitted vendor bids runs from exactly one in NSW to three in SA to no stated limit in Victoria. Cooling-off after a passed-in auction differs in every state.

Do I have to register to bid at an auction?

It depends on the state. New South Wales, Queensland and South Australia require bidder registration with proof of identity and an allocated bidder number. Victoria and Western Australia do not require registration to bid at a property auction.

Is there a cooling-off period when you buy at auction?

No. A sale under the hammer at a public auction carries no cooling-off period for the buyer in any Australian state. That is one of the main reasons vendors choose the method.

What about buying after the auction, if the property passes in?

This is where the states diverge sharply. Victoria excludes cooling-off for three clear business days after the auction. New South Wales excludes it only if contracts are exchanged the same day. Queensland excludes it until 5pm on the second business day, and only for someone who was a registered bidder. South Australia excludes it on the auction day itself. Western Australia has no statutory cooling-off at all.

How many vendor bids can be made at an auction?

New South Wales permits exactly one. South Australia permits up to three, all below the reserve. Victoria permits one or more with no stated numeric limit. Queensland and Western Australia permit them up to the reserve price. Every state requires the auctioneer to announce each one.

Does the reserve price have to be in writing?

In New South Wales it is a prescribed condition of sale, and in Queensland the seller must put the reserve in writing before the auction. The position in Victoria, South Australia and Western Australia was not established to a publishable standard when this page was written, so confirm it with your agent or conveyancer.

Who decides if there is a dispute about a bid?

In New South Wales the auctioneer is the sole arbiter under the prescribed conditions of sale, and Queensland’s standard conditions of sale give the auctioneer the same discretion, including the ability to reopen bidding at the last accepted bid. Check the conditions of sale for your own auction, since this is usually a contractual term rather than a statutory one.

Can a bid be accepted after the hammer falls?

No, in the states where this is expressly addressed. Victoria and New South Wales both prohibit accepting a bid after the fall of the hammer, and in Victoria the auctioneer must announce that prohibition before bidding starts.

Which state has the strongest buyer protections at auction?

It depends what you mean by protection. New South Wales has the tightest bidding controls: registration, a single vendor bid, and a confidential bidders record. Western Australia has the fewest statutory protections, with no registration and no cooling-off regime at all.