Unless you want to start a National organisation, registering a incorporated association is done at the State or Territory level.
Information on the processes for incorporated associations for each state are here:
NSW – https://www.fairtrading.nsw.gov.au/asso … operatives
QLD – https://www.qld.gov.au/law/laws-regulat … or-profits
SA – https://www.cbs.sa.gov.au/associations-cooperatives
Tas – https://www.cbos.tas.gov.au/topics/club … sociations
ACT – https://www.accesscanberra.act.gov.au/s … -questions
NT – https://nt.gov.au/industry/licences/inc … sociations
Vic – https://www.consumer.vic.gov.au/clubs-a … sociations
WA – https://www.commerce.wa.gov.au/consumer … -and-clubs
The rules for each state are similar but the laws, processes, and fees are different in each state.