Departments sit at the centre of ministerial government
Commonwealth departments support ministers, develop policy, administer programs and coordinate government business. They are part of the executive branch and are led administratively by departmental secretaries under the Public Service Act and related legislation.
A department is usually closely connected with a minister's portfolio, but even within a portfolio there may be multiple agencies with different legal structures and degrees of independence.
Statutory authorities are created or empowered by legislation
A statutory authority or agency may be established by an Act that sets out its functions, governance, powers and accountability arrangements. Some have boards, commissioners or chief executives appointed under legislation rather than operating as an ordinary departmental division.
The enabling Act matters because it can limit ministerial direction, require independent decision-making or create specific reporting duties to Parliament.
Independence varies by agency
Some bodies are deliberately designed to exercise powers independently, particularly where impartial regulation, investigation or review is important. Others are more directly subject to ministerial directions or government policy.
The label 'independent agency' should therefore be checked against the actual legislation. Independence can apply to specific decisions without making the entire organisation completely separate from government.
Public servants and statutory office-holders
Employees in departments are generally Australian Public Service employees, while statutory authorities can have different staffing arrangements. Statutory office-holders may hold personal legal powers that cannot simply be taken over by a minister or departmental secretary.
This distinction becomes important in stories about regulators, commissioners and review bodies, where the question is often who has legal authority to make the contested decision.
How to work out who controls what
Start with the agency's enabling legislation, portfolio statement and official governance page. Then distinguish policy responsibility, funding responsibility, appointment powers and operational decision-making.
That approach is more accurate than assuming every body in a minister's portfolio is directly controlled by the minister in every respect.
Primary sources and further reading
We use authoritative Australian institutions as the starting point for this explainer. Follow these links for the underlying rules, official guidance and current details.