This seller on ebay sells Aussie WW2 Dog Tags, though you'd have to know what to put on them.
http://search.ebay.com.au/_W0QQsassZdogtagman1
Here's another Aussie Dog Tag Supplier.
http://www.oze-id.com.au/Prod_0Australian.php
Here's a general piece about Aussie Dog Tags from the AWM.
"In 1906, Australian soldiers were issued with a tin disc rather than the tape, and given orders that this was to be worn around the neck. The discs were stamped with the soldier's name, service or regimental number, religion, and unit. During the First World War this was increased to two fibreboard discs, one round and one octagonal. The octagonal disc, sometimes coloured green, was to remain with the body of the soldier to aid in identification should the body need to be exhumed. The circular disc, sometimes coloured red, was used to identify the belongings of the soldier and be sent home. Folklore has it that these colourings were to aid soldiers in remembering which tag went where: red meant blood and was to be taken, since the soldier was dead; green meant grass and was to stay with the body.
During the Second World War, the fibreboard discs were replaced with metal ones, which would not rot in wet conditions. They were secured around the neck by cotton tape (which did rot in the jungle), a leather thong, or a metal chain. The latter would have been provided by the soldier individually."