Malcolm Fraser, the former Australian prime minister who was notoriously catapulted to power by a constitutional crisis that left the nation bitterly divided, died on Friday his office said. He was 84.

"It is with deep sadness that we inform you that after a brief illness John Malcolm Fraser died peacefully in the early hours of the morning," a statement released by his office said.

"We appreciate that this will be a shock to all who knew and loved him, but ask that the family be left in peace at this difficult time." it added.

With the cultivated Australian accent of the old money families and a stony countenance that cartoonists lampooned as an Easter Island statue, many mistook him for a classical conservative.

But he later became a vocal critic of conservative politics in Australia and a thorn in the side of the center-right Liberal Party that he once led and eventually quit in disgust in 2010 following the party's election of the current Prime Minister Tony Abbott as its leader.

Fraser became the unelected leader of an unsuspecting nation in 1975 when the then Governor-General John Kerr took the unprecedented step of dismissing the chaotic, frenetically reformist government of Prime Minister Gough Whitlam.

It was a development that most Australians had not thought possible. Many were outraged that the Australian representative of Queen Elizabeth II, Australia's distant constitutional head of state, would dare oust a democratically-elected government.

An indignant Whitlam branded Fraser "Kerr's cur," and urged voters to "maintain the rage" at the ballot box.

A month after taking power as a caretaker government, Fraser's conservative coalition won a clear victory over Whitlam's center-left Labor Party. Fraser won another two three-year terms.

But his legitimacy as a leader never recovered from the controversy over how he got there. The "Kerr's cur" tag lingered in the nation's memory decades later.

Years after Fraser and Whitlam's parliamentary careers ended, the two political foes became friends. They shared a disappointment that their rival parties had both shifted to the right on issues including the treatment and detention of asylum seekers.

Whitlam died in October last year aged 98.