Australian Red Ensign
The Australian Red Ensign resulted from the 1901 Commonwealth Government Federal Flag Design Competition which required two entries: a flag for official use by the Commonwealth Government and one for the use of state and local governments, mercantile marine, private organisations and individuals. The winning design was based on the traditional British Red Ensign and featured the Southern Cross and Commonwealth Star.
The Australian Red Ensign is simply a red version of the current Australian National Flag, using the same shade of red as the Cross of Saint George which is part of the Union Jack present in the canton.
In 1903, the design of the Southern Cross constellation was altered from five stars with nine, eight, seven, six and five points respectively, to four stars with seven points and one with five points. The original variety of points was an indication of the relative brightness of each star as it appeared in the night sky.
In 1908, the current Commonwealth star of seven points replaced the earlier six-pointed star.
Following federation in 1901, the topic of national colours for British ships registered in Australian ports was addressed by the Navigation Act, which provided that such ships (i.e., civilian ships) should wear the Australian Red Ensign. Technically private non-registered vessels were liable to a substantial fine if they did not fly the British Red Ensign as they were not formally covered by the Navigation Act. However, an Admiralty Warrant was issued on 5 December 1938 which authorised such non-registered vessels to fly the Australian Red Ensign, too. Australia enacted fully domestic shipping legislation in 1981. The Shipping Registration Act of 1981 reaffirmed that the Australian Red Ensign was the proper "colours" for Australian registered ships and that smaller (i.e., less than 30 tons) pleasure and fishing craft could fly either the Australian Red Ensign or the Australian National Flag but not both at the same time.
From 1901 to 1954 the Red Ensign was used as the national flag by State and local governments, private organisations and individuals.
In 1941, Prime Minister Robert Menzies stated that there should be no restrictions on private citizens using the Blue Ensign on land and, in 1947, Prime Minister Ben Chifley reaffirmed this position but it wasn't until the passage of the Flags Act 1953 that the restriction on civilians flying the Blue Ensign was lifted after which use of the Red Ensign on land became a rarity.
Since 2008, 3 September has been officially commemorated as both Australian National Flag/Merchant Navy Day which allows the Australian red ensign to be flown on land for the occasion as a matter of protocol.  
Other Australian Red Ensigns
Red Ensign of the Commonwealth Lighthouse Service
Red Ensign of South Australia (1870-1876)
Red Ensign of Victoria (1870)
- "Shipping Registration Act 1981". pp. 10, 22. Retrieved 2012-04-25.
- Commonwealth of Australia Gazette, S 321, 28 August 1996.
- Commonwealth of Australia Gazette, No. GN 26, 2 July 2008