It's a buyers market and you don't have to sign their contract. You can add a few clauses of your own.

Never feel pressured to sign. If you're planning to pay for any building work in Australia, there are laws to protect you, but remember once you have signed, you have obligations.

It's important that you understand the risks, obligations and responsibilities. If they are not clear to you, please, please take the time to seek advice.

Any home building or renovations contract you are looking at should also, when applicable to the proposed work, include quite specific information.
Quite often, the builder is 'happy' to omit some of these details and leave them 'unspecified' ie: "but that wasn't in the contract".
Minimising your risks involves making sure you know what you want and that your builder does too. Gaps and omissions rarely help you, the buyer.
If your builder won't give you a copy of the contract to take away and read well before you sign it, then get rid of them.
Once you have signed a contract, you normally have time to reconsider.
If you haven't already, get advice.
You can cancel or request changes to the contract during your cooling off period.

Any home building or renovations contract you are looking at should:
State the number of days allowed for each type of foreseeable delay and inclement weather
State a start and finish date, with allowances for delays
If the start date is not known, the contract must state:
How the start date will be determined
That the builder will do everything that is reasonably possible to start work as soon as possible
The number of days required to finish the work once it has started

There are also penalty clauses that can be included in your contract should the builder:
make mistakes
breach the contract, or
take too long

Speak to a lawyer about these.

Make sure:
You have run a search (licence and background eg: Always Check Your Builder) on your proposed builder
The builder has confirmed the site is suitable for the proposed work, and has obtained foundation data and a soil report. It is their responsibility to satisfy themselves that the foundation data is accurate
The work has the required building and/or planning permits, or the contract states who is responsible for obtaining these
The work is clearly and comprehensively described in the contract, including plans or specifications and any other relevant documents
You have included all special requirements and finishes in the plans and specifications
Fixtures and fittings included in the contract but not specifically identified, or of unknown price, are clearly stated as Provisional sum items or Prime cost items, and adequate costs are allowed for these
The builder has provided a current certificate of domestic building insurance, covering the building project's address
The requested deposit is within the legal limit
The price and timing of progress payments are legal and clearly stated, and include mechanisms or agreements for independent inspections at specific milestones, usually as a necessary prelude to any progress payment
You understand the procedure for changes to the contract
You and the builder share an understanding of what is 'reasonable access' to the building site
The builder or tradesperson must give you a copy of the contract when you have both signed it