Have a look here:
Airservices Australia - Aeronautical Information Package (AIP) (airfield directory)
Off the top of my head: Bankstown (listed under sydney) is security controlled, Camden is a way out, and isn't, and Kingsford smith is kinda off limits
As has (I think) been noted, you actually can't 'exercise the priviledges' of a PPL in australia without having an ASIC/AVID. However, I'm less clear how that would apply for a validated foreign license.
The renewal process (er, for the ASIC that is!) at least isn't too bad, I got mine with little hassle - thought there are horror stories around.