Australian issued documents must be Notarized 1st then Apostilled | Legalized from DFAT i.e. Department of Foreign Affairs and Trade.
State Documents
The State documents should be authenticated by the suitable office within the state Secretary of State's office . The document may then be authenticated by the Australia. Department of State Authentications office. The document may then be authenticated by the foreign embassy or consulate within the Australia. Normally , And you're going to migrate Australia you wish get notarized your document and submit to HRD attestation | apostille and MEA attestation | apostille. Finally you can submit your document for the Australia embassy for legalization | apostille.