The Chief of the Defence Force and the Secretary for the Department of Defence jointly manage the Defence organisation under a 'diarchy'.
The term diarchy, while it derives much from section 10 of the Defence Act 1903, in fact has no specific legislative basis. Rather, it has become a commonly used term to describe the relationship between the Chief of the Defence Force and Secretary, who both work for the Minister for Defence. The diarchy is a governance structure unique in the Commonwealth public service. It reflects the amalgamation of what were previously discrete entities into the one Defence organisation.
The diarchy reflects the individual responsibilities and accountabilities of the Chief of the Defence Force and the Secretary, and also their joint responsibilities and accountabilities, in ensuring that the Defence organisation delivers to the Australian Government outcomes that go to meeting the goal of defending Australia and its national interests.
The manner in which the diarchy operates is further set out in directions given to the Chief of the Defence Force and Secretary by the Minister for Defence. In the past, the Minister issued separate directions to the Chief of the Defence Force and Secretary. Since the mid-nineties, it has been the practice that the Minister has issued a joint ministerial directive to the Chief of the Defence Force and Secretary. The joint directive provides detailed ministerial direction to both officers on how the Minister expects them to conduct their business in delivering Defence outcomes to the Australian Government. In particular, the joint ministerial directive is used to detail the respective roles, responsibilities and accountabilities of the Chief of the Defence Force and Secretary, to detail ministerial expectations and to detail pragmatic implementation changes. Consequently, the joint ministerial directives issued from time to time are critical in identifying how the diarchy is to operate in practice.