NCC 2022 does not force you to install a floor waste in wet areas. But if you do install one (even voluntarily), you must grade the floor to drain to it. Clause 10.2.12 now makes this mandatory, with a continuous fall between 1:80 (minimum) and 1:50 (maximum) to the waste.

What to do: if your bathroom or laundry includes a floor waste, make sure the screed and set-out allow compliant falls before waterproofing and tiling.

Read more: https://www.abcb.gov.au/ncc-navigator/waterproofing-houses