Aus is one of the few countries who will hand out a CPL to foreigners based on their national certificate. USA and Canada will only provide CPL with Green Card or work permit i.e. You no get if you cant work there, PPL easy, but NO commercial.....so.. Are you an Australian with an FAA certificate, which remains valid without currency? If so current or not conversion is not the issue, exercising priviliges will require currency in any case. No medical...... Now THAT could be an issue.
HD