Here you will find a link to the oficial Australian Trademark Search. In the same you can find identical trademarks to the one you look for but keep in mind that not only identical trademarks are an impediment to register a trademark but also similar trademarks are. To locate all relevant trademarks before applying for registration of your trademark in Austrialia you should hire professional services.
If you wish to register a trademark in Australia, is also advisable to hire the services of a professional who not only does the application correctly mark but also offers a surveillance service.