It is only recently that "Index Only Record" has been added to the various amalgamated indexes that Ancestry labels as "Australia, Birth Index, 1788-1922". Previously these had been referred to as "Vital Records" .....
The Australian version seems to suggest that there is one central BDM covering all of Australia. In fact, there is NO central registry covering all of Australia. Each of the former British Colonies that are the foundation states for the Commonwealth of Australia, had and continue to have their own Parliaments, and their own Official institutions. So each of those six states have their own BDM registries, their own rules and regulations governing their own registeries, and their own ways of providing official BDM certificates.
I am aware of many family history buffs/groups who discreetly appealed to the commercial websites asking them to acknowledge that the Australian 'records' were simply databases of amalgamated existing indexes that have been available on CD and microfische etc long before the commercial websites were developed.
So for example, Ancestry has NSW BDM births to about 1909. NSW BDM itself has its own website, and it displays birth registrations for all but the previous 100 years, so as it is 9 November 2015, as I write, it will display birth registrations up to 8 November 2015.
Cheers, JM