High Quality Content by WIKIPEDIA articles! The Prime Minister of the Commonwealth of Australia is the highest minister of the Crown, leader of the Cabinet and Head of Her Majesty`s Australian Government, holding office on commission from the Governor-General of Australia. The office of Prime Minister is, in practice, the most powerful political office in Australia. Despite being at the apex of executive government in the country, the office is not mentioned in the Constitution of Australia specifically (although the Constitution does refer to "The Queen`s Ministers of State for the Commonwealth " in general) and exists through an unwritten constitutional convention.