The short version
Concessional routes under the Road Vehicle Standards Act
Australia does not operate a simple single age rule. Imports are handled through the Road Vehicle Standards legislation and its concessional pathways, and the requirements are more involved than in North America.
No straightforward 25-year exemption
Australian import approval is granted against specified pathways rather than a blanket age exemption. Do not assume US guidance applies.
Approval before shipping
Import approval is generally required before the vehicle arrives. Shipping first and arranging approval later is the expensive mistake.
Asbestos is checked
Australian border controls take asbestos in older vehicle components seriously, and testing or certification may be required.
State registration is separate
Each state and territory sets its own registration and compliance requirements on top of federal import approval.
Who decides
Australian Department of Infrastructure, Transport, Regional Development, Communications and the Arts; your state or territory road authority.
This page is a plain-language summary for orientation. It is not legal or customs advice, and it can go out of date. The authorities named above are the only reliable source for your own situation.