Vehicle registration plates are commonly known as number plates and since 2000 the State or Territory Government has issued them. Prior to 2000 the Commonwealth government issued some plates. The number plates are assigned to a vehicle for life and may be recalled if they become unreadable or for any other reason that the government considers necessary. New plates are issued if the vehicle moves to another state.

Originally, Australian number plates consisted of white characters on a black background. Every state and territory was assigned plates, which followed the same format, three letters followed by three numbers. For example, the plates assigned to Queensland ran from QAA000 to QZZ999 and Victoria received GAA000 through to GZZ999. While this system was effective for a time, by 1980 many states had run out of available combinations and the system had to be abandoned. The Australian Capital Territory, however, continued to issue this style of plates until the end of the 1990s.

Following the demise of the old system, all states and territories were left to issue their own design of plates. Some, such as Victoria and New South Wales, kept the original three letter and three number combination, but started again from scratch, while Queensland adopted three numbers followed by three letters. Each state has continued to adapt their number plate system. The only state still using the format of three letters followed by three numbers is Victoria.

All vehicles registered in Australia are required to have a sticker on the lower left hand corner of the windscreen or rear window, which changes annually on a six year cycle; blue to red to purple to brown to green to orange. These labels are an indication that the vehicle’s registration fee is up to date.