For purchasing property in NSW, the principle of "caveator emptor" applies. This means it is the buyer's responsibility to check the quality and suitability of the property before entering into the contract for sale. Properties are usually sold "as is", unless it is an off-the-plan purchase where the property construction has not finished.
MyProperty Conveyancer always recommend that you purchase a strata report or a pest/building inspection report with a third-party inspector prior to entering into contracts or before your cooling-off period expires. These may uncover "latent" or hidden defects of the property which can affect the price you offer or whether you wish to proceed with the purchase at all.
After the contracts have been "exchanged" and dated, it can be difficult to arrange the Vendor to rectify issues or reduce the price as the Vendor is not obligated to agree to your request.