To own a .com.au or .net.au you must be an Australian registered company, or business with a registered business number (ABN, BRN, BN).
I bought one last week and I need to fill in my business details for the 3rd time to get it right, even though I am legit. That's why you won't see any spam sites that are .com.au.
While you might be able to bypass the rules by a push that retains the previous details, pretty much whichever way you do it will be in breach of the rules - and risking losing the domain.
Try asking at DNTrade - just Aussies there.
The solution might be to find an Australian (with a registered business) you trust as your proxy.