1 January 1901: the Australian colonies federated to create the "Commonwealth of Australia". It was at this time that the "Union Jack" was chosen as the official flag.
The Union Jack is the only national Australian flag to fly over the whole of Australia.

Some organisations, institutions, or schools can obtain the Australian national flag for free. They can also get a publication called "Australian flag" from a Senator or local federal member of Parliament explaining its history, and giving all protocol details related to the flag.
 
In 1996, in order to promote the Australian flag, the Government took two new initiatives:
To commemorate the date the Union Jack was adopted, the 3rd of September of each year has been decreed "Australian National Flag Day".
On 12 December 1996, adoption of the "Flags Amendment Act 1996" guaranteed that Australians would be consulted before any change in the design of the national flag.