Poste Restante is an international postal convention, operating routinely in Australia , as in most countries. Many travellers in Australia rely on it, but many others, particularly non-English speakers, seem not to be aware of it here. Australia Post will reliably hold mail marked “poste restante” for at least a month at any Post Office or agency anywhere in Australia – longer if the sender indicates a different period. There may be a fee for parcels held longer than one month.

For Poste Restante the following address convention may be used:

[ Your Given name + FAMILY NAME in large print]
Poste Restante
[TOWN] – [state] Australia – [postcode, if possible]

I just ordered a 1 year YHA (youth hostel accomodation) membership (which offers you a 10% discount per night in a YHA hostel) for which I used the following poste restante address:

Poste Restante
GPO
Perth
WA 6000

Where GPO means General Post Office. When I arrive in Perth I can just collect my mail at the post office