Game tester is an entry-level employment position in the gaming industry. In Australia, there are relatively few gaming companies, owing to its small population compared to other markets. Steady employment is particularly difficult to come by, unless the individual receives a promotion to quality assurance (QA) lead or moves elsewhere within a company.
Search for a job using a specialized listing site or by contacting local companies directly. Avoid recruiting websites that charge money upfront with no guarantee of a job. Timing is critical since game companies need a varying number of testers at different phases of development.
Contact major publishers that have offices in Australia. The companies that sell the major game consoles also run significant international testing operations in Australia, sometimes for quality assurance, but mostly for focus group purposes.
Familiarize yourself with the growing Australian games industry. Try building up credentials as a tester or perhaps in some other job in the game industry by working as a contractor for an Australian developer.
Polish your writing skills. Game testers spend almost as much time writing reports about products, bugs, exploits and other issues. Getting promoted---and staying employed as a tester---will depend mostly on the professionalism, communication ability and development of technical skills on the part of the tester.
Consider moving to Sydney. Most major game developers and publishers are have offices there, and game tester jobs often require testers show up at work with less than 24 hours' notice.