Department of Defence (Australia)

Federal defence department of the Australian Government

the civilian department of the Australian Public Service which supports the Australian Defence Force

Defence Australia is a department of the Government of Australia charged with the responsibility to defend Australia and its national interests. Along with the Australian Defence Force (ADF), it forms part of the Australian Defence Organisation (ADO) and is accountable to the Commonwealth Parliament, on behalf of the Australian people, for the efficiency and effectiveness with which it carries out the Government's defence policy. The head of the department, who leads it on a daily basis, is the Secretary of the Department of Defence (SECDEF), currently Greg Moriarty. The Secretary reports to the Minister of Defence, Richard Marles.

Australia has had at least one defence related government department since Federation in 1901. The first Department of Defence existed from 1901 until 1921. In 1915, during World War I, a separate Department of the Navy was created. The two departments merged in 1921 to form the second Department of Defence, regarded as a separate body. A major departmental reorganisation occurred in the lead up to World War II. The Department of Defence was abolished and replaced with six smaller departments – the Defence Co ordination (for defence policy, financial, and administrative matters), three "service departments" (Army, Navy, and Air), the Supply and Development (for munitions and materiel), and Civil Aviation. In May 2022, the department was renamed Defence Australia. The Australian Department of Defence, along with the Australian state and other governments are known to fund the Australian Strategic Policy Institute (ASPI), a defence and strategic policy think tank based in Canberra, Australian Capital Territory.

The Chief of the Defence Force (CDF) and the Secretary of the Department of Defence (SECDEF) jointly manage the Australian Defence Organisation (ADO) under a diarchy in which both report directly to the Minister for Defence and the Assistant Minister for Defence. The ADO diarchy is a governance structure unique in the Australian Public Service.

The Secretary of the Department of Defence (SECDEF) is a senior public service officer and historically the appointees have not come from military service. Name Post nominlal's Date appointmentcommenced Date appointmentceased Term in office Notes Ref(s) , PVNF 1901 1910 Pethebridge was acting Secretary 1906–1910 1910 1918 Trumble was acting Secretary 1914–1918 1918 1927 1927 1937 1937 1956 28 October 1956 5 January 1968 1 May 1968 1970 March 1970 August 1979 August 1979 6 February 1984 6 February 1984 15 October 1986 February 1998 31 August 1999 Appointment terminated by the Governor General on the recommendation of Prime Minister Howard. Barratt fought the decision in the Federal Court, losing on appeal. 21 October 1999 20 October 2002 11 November 2002 3 December 2006 4 December 2006 13 August 2009 13 August 2009 5 September 2011 5 September 2011 18 October 2012 4 September 2017 Incumbent