Prime Minister of Australia prime minister, otherwise William McMahon63. Robert Menzies was the oldest person to ever be prime minister, leaving office at 71 years old. The longest-serving Prime Minister was Sir Robert Menzies, who served in office twice: from 26 April 1939 to 28 August 1941, and again from 19 December 1949 to 26 January 1966. In total Robert Menzies spent 18 years, 5 months and 12 days in office. He served under the United Australia Party and the Liberal Party respectively. The shortest-serving Prime Minister was Frank Forde, who was appointed to the position on 6 July 1945 after the death of
Prime Minister of Fiji on 10 October 1970, when Fiji attained its independence from Britain. Mara previously served as Fiji's first an only Chief Minister, from 20 September 1967 (while Fiji still was a British colony). Mara's first term as Prime Minister lasted until 13 April 1987. He returned to the office for the second term on 5 December 1987, serving until 2 June 1992. As of 2014, Mara is the longest-serving Prime Minister of Fiji. ! colspan=9| Prime Ministers of the Dominion of Fiji ! colspan=9| Prime Ministers of the Republic of Fiji Prime Minister of Fiji The Prime Minister of the Republic