The fastest way for you to find out is to call Hertz in Australia. The telephone number for Hertz #1 Gold is 1800 500 023.
It's doubtful, but if Hertz are willing to Status Match? - Please let us know! Then, it may be similar to an airline status match you have to fax them your rental history and possibly invoices from last year. Feeding over 30 pages of invoices into a fax may take a while.
In Australia the number of rentals needed for *5 is 10/year, and for PC it is 30/year.