From their website:
"Researching family history is a favourite hobby for many people. The National Archives of Australia holds many records in which you might find information about your ancestors. This is the place to come if your family members served in the Australian armed forces or if they migrated to Australia during the 20th century.
You can view original archival records in one of our reading rooms around the country. We are also providing access to more and more information and records online, so you can both prepare and undertake research from home.
You can begin your family journey into the National Archives right now. Have a look at the information, case studies, resources, and preservation sections listed below."