One Nation. Fantastic Policy. Indigenous Rorts, page-85

I'm not sure that there is a definitive DNA test for indigeneity. A cursory Google search suggests that there are insufficient samples to compare against.
Story here of a person who identifies as indigenous doing a DNA ancestry test that came back with top matches for Portugal and Basque.
https://www.thesaturdaypaper.com.au...geneity-and-dna-ancestry-tests/15399540007021

Apparently Australia has changed the way it defines Aboriginality over the years.

https://www.aph.gov.au/About_Parlia...rary/Publications_Archive/CIB/cib0203/03Cib10

The definition of Aboriginality has a long and contentious history in Australia. Different classification systems (many with significant personal and social consequences) have moved in and out of fashion.

Even today, two very different definitions are concurrently in use. One, predominating in legislation, defines an Aboriginal as 'a person who is a member of the Aboriginal race of Australia'.

The other, predominating in program administration but also used in some legislation and court judgements, defines an Aboriginal as someone 'who is a member of the Aboriginal race of Australia, identifies as an Aboriginal and is accepted by the Aboriginal community as an Aboriginal'.




https://aiatsis.gov.au/research/finding-your-family/before-you-start/proof-aboriginality

Your Aboriginal or Torres Strait Islander heritage is something that is personal to you. You do not need a letter of confirmation to identify as an Indigenous person. However, you may be asked to provide proof or confirmation of Aboriginal and/or Torres Strait Islander heritage when applying for Indigenous-specific services or programs such as:

• grants (such as Indigenous housing loans, research and study grants)
• university courses (with specific positions for Indigenous students)
• Centrelink and housing assistance (Indigenous-specific)
• employment (Indigenous identified positions)
• school programs for Indigenous students.

Government agencies and community organisations usually accept three ‘working criteria’ as confirmation of Aboriginal or Torres Strait Islander heritage:

• being of Aboriginal or Torres Strait Islander descent
• identifying as an Aboriginal or Torres Strait Islander person
• being accepted as such by the community in which you live, or formerly lived.

All of these things must apply. The way you look or how you live are not requirements.
Government agencies, universities and schools will often supply you with their particular guidelines, and ask you to complete a form or provide a letter of 'Proof' or ‘Confirmation of Aboriginal and/or Torres Strait Heritage’.