Australia mostly follows the Brits with regards to floor numbering.

Some organisations follow the US standard, e.g. ANU: https://services.anu.edu.au/financial-management/assets/numbering-of-floors-and-rooms-in-new-buildings

But mostly we follow the Brits. Except for a heap of weird buildings on slopes, etc. where the ground floor is actually Floor 2 or something else...