From -

https://ipfs.io/ipfs/QmXoypizjW3WknFiJnKLwHCnL72vedxjQkDDP1mXWo6uco/wiki/Vehicle_registration_plates_of_Australia.html

About 1951–2, Australian automobiles were to adopt a broad scheme across
all states and territories for vehicle number plates. Both NSW and Victoria
had previously issued plates with 2-letter, 3-digits, white on a black
background. However, while implemented, this was not entirely popular as
some states and territories preferred their own identity reflected on their
vehicles instead. They were 'meant' to use the following proposed scheme:

New South Wales: AAA-000 to FZZ-999 – Exited scheme July 2004

Victoria: GAA-000 to MZZ-999 (Iaa-nnn series skipped initially, but used
after the Laa-nnn series) – Exited scheme August 2013

Queensland: NAA-000 to QZZ-999 (Oaa-nnn series initially skipped by
Queensland) – Exited scheme July 1977 partially

South Australia: RAA-000 to TZZ-999 – Exited scheme October 2008

Western Australia: UAA-000 to VZZ-999 (V was not used; issued X after U ran
out) – Exited scheme January 1979

Tasmania: WAA-000 to WZZ-999 – Exited scheme 1970

Northern Territory: XAA-000 to XZZ-999 (not taken up; stayed with 6 numeric
digits) – Exited scheme June 2011

Australian Capital Territory: YAA-000 to YZZ-999 – Exited scheme July 1998

Commonwealth GOVERNMENT ZAA-000 to ZZZ-999 (with first Z in red), issued
Australia-wide

X=X=X