Have a look at the Office of Fair Trading Qld "Buy a new car" page that sets out: Cooling-off period There is no cooling-off period on the sale of a new car. Make sure you are happy with the car and the terms of the contract before signing it.
A new car has never been licensed or registered. A demonstration car (‘demo model’) is not classed as a new car.
A cooling-off period is an amount of time given to you to end the contract without large penalties. Used car purchases have a cooling-off period.
However, while you can't terminate because you change your mind, you still have: 9 consumer guarantees that apply to any goods you buy from businesses in Queensland.
You can seek a remedy (a solution to the issue) if a business sells you a vehicle that doesn’t meet these guarantees. The business will have to attempt to correct any fault, deficiency or failure. This might be a refund, repair, replacement or compensation for the drop in value of the product. When there is a major failure, you can:
reject the vehicle and choose a refund or a replacement
ask for compensation for any drop in value of the vehicle.