<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by SPN Lifer:
Obviously one would need an Australian mailing address. But what else would one need? Australian tax number, or other sort of financial registration? Must one be a legal resident?</font>
There are two issues here: what the bank would require and what they'd be required to require by the law. They'd be required by the cash transactions act to collect proof of your identity. It'd be very hard for a non-resident to have enough Australian ID, so you'd probably have to use your passport, which would tend to tip them off that you don't live here. No requirement for tax file number at all though.
There are a few things that are quite different here to the US. For one, all information on your credit record apart from ongoing commitments and bankruptcies, get deleted after 5 years. So, after you've had a credit card for a while, the banks have very little to go on but their own records. (eg. 3/4 of my credit cards are no longer on record with the credit reference agency)