If you look at where you can buy them on this site, it says that if you are willing to pay for shipping and wait for awhile, they will ship it. So I think so!
Actually, Australia has restrictions on size of packages coming in when shipping USPS Priority or Express International (which are the more reasonably priced methods). The only options are USPS Global Express Guaranteed which carries a hefty price - over 300 US dollars for shipping alone for the large or XL sizes.
I do know some people have found materials in Australia - perhaps check the "Australia/New Zealand" section for possible material sources. Good luck!
You could try (broken link removed), Australian Cavy Sanctuary (ACS). I'm not sure if they ship or not though. Or you could post in the ACS forums (broken link removed) and see if anyone can help you out. Very friendly bunch there.
All of the materials to make these cages can be found in Australia, though sometimes under different names.