In 1909, the Defence Act 1909 (Commonwealth) prevented those who were not of 'substantially European descent' from being able to enlist in any of the armed forces. This act was inforced when Australia delared war on the 1st August 1914. By October 1917, when recruits were harder to find this restrictions was eased. A new Military Order stated: "Half-castes may be enlisted in the Australian Imperial Force provided that the examining Medical Officers are satisfied that one of the parents is of European origin."

In 1914 Aboriginal and Torres Strait Islanders were not officially classified as citizens of Australia. Under the Protectors' Acts they could not enter a public bar, vote, marry non-Indigenous partners or buy property. Despite this many still wanted to support Australia by being involved in the war.  AIATSIS "why did they join" site states that Aboriginal and Torres Strait Islander soldiers joined as like every other adventurous young Australian male, wanting to go out and see the world, get paid really good money, see some action and “be home before Christmas”.

A soldiers ability to survive in a hostile countries relied heavily on his commardes.  In the heat of battle a man is not judged by his race or colour, he is judge on other scales. For the first time Aborginal and Torres Strait Islanders did not experience racism.  They recieved the same pay as their Australian counterparts and were treated accordingly. Only when returning to Australia did the racisim raise it's ugly head again with these solders being shunned on arrival home, the denial to attend ANZAC ceremonies, their sacrifices ignored and their families oppressed even further by their respective State and Federal governments. They were denied the Discharge Soldier Settlement Scheme".

Under the Discharged Soldiers’ Settlement Act and Regulations of 1917, every discharged member of the armed forces, except Aboriginal and Torres Strait Islander peoples was entitled to apply for land and financial assistance.

http://www.archives.qld.gov.au/Researchers/CollectionsDownloads/Documents/BG35SoldierSettlement.pdf

When war broke out in 1914, many Indigenous Australians who tried to enlist were rejected on the grounds of race; others slipped through the net. In 1917, when recruits were harder to find and one conscription referendum had already been lost, restrictions were cautiously eased.

A new Military Order stated: "Half-castes may be enlisted in the Australian Imperial Force provided that the examining Medical Officers are satisfied that one of the parents is of European origin." This is as far as the officials would go.

In the John Oxley Collection is the Accession Number: 5763 Title: Barambah Aboriginal Settlement Photograph Album  taken on the 3rd October 1925 by James Stopford, shows this push to acquire new soldiers into the war.  

Hall, Robert A., The Black Diggers: Aborigines and Torres Strait Islanders in the Second World War, Allen & Unwin, Sydney, 1989 – reprinted several times

Huggonson, David, Villers-Bretonneux: A Strange Name for an Aboriginal Burial Ground, Journal of the Royal Historical Society of Queensland volume 14 issue 7: pp. 285-288
http://www.textqueensland.com.au/item/article/e31a048805cd18f65d8d995473bab979

Jackomos, Alic, Forgotten Heroes: Aborigines at war from the Somme to Vietnam, Victoria Press, Melbourne, 1993

Peter Dennis, Jeffrey Grey, Ewan Morris & Robin Prior, The Oxford Companion to Australian Military History, Oxford University Press, Melbourne, 1995

Powell, Alan, The Shadow’s Edge: Australia’s northern war, Melbourne University Press, Melbourne, 1988

Australian War Memorial
Resource Book: Memorial Box 03 - Too dark for the Light Horses
http://www.awm.gov.au/education/box/03_res_book.pdf