The Prime Minister of Australia is the head of government of Australia. The individual who holds the office is the most senior Minister of State, the leader of the Federal Cabinet. The Prime Minister also has the responsibility of administering the Department of the Prime Minister and Cabinet, and is the chair of the National Security Committee and the Council of Australian Governments. The office of Prime Minister is not mentioned in the Constitution of Australia but exists through Westminster political convention. The individual who holds the office is commissioned by the Governor-General of Australia and at the Governor-General's pleasure subject to the Constitution of Australia and constitutional conventions.