The Queen was told of Sir John Kerr's consideration of the dismissal of prime minister Gough Whitlam months before the historic decision of November 11, 1975.
But the former governor-general insists he did not inform the palace in advance of his final decision.
The National Archives of Australia on Tuesday released details of letters between the former governor-general and the Queen in the lead-up to the dismissal of the Whitlam government.
In a letter to the Queen after he sacked Whitlam, Sir John wrote: "I should say I decided to take the step I took without informing the palace in advance because, under the Constitution, the responsibility is mine, and I was of the opinion it was better for Her Majesty not to know in advance, though it is of course my duty to tell her immediately."
The letter included three attachments: the dismissal letter to Whitlam, a legal opinion from the then chief justice Sir Garfield Barwick, and a letter from the then opposition leader Malcom Fraser.
Archives director-general David Fricker also detailed to reporters at a briefing in Canberra a letter from Sir John to the Queen dated September 12, 1975.
"I'm also keeping my mind open as to the constitutional issues. If the Prime Minister and the Leader of the Opposition get into a battle in which the Senate has defeated the budget, the Prime Minister refuses to recommend a dissolution, my role will need some careful thought," Sir John wrote.
Sir John included a press clipping which explored the options of dismissal of the Whitlam government.
"So on the 12th of September 1975, Sir John is laying this out," Mr Fricker said.
The Queen's secretary Sir Martin Charteris wrote back to Sir John referring to the practice that if a parliament refused supply - legislation allowing money to pay for government - it was constitutionally proper to grant a dissolution of the parliament.
Sir Martin later wrote back to Sir John, a week before the dismissal, acknowledging he had "reserve powers".
"With great respect, I think you are playing the vice-regal hand with skill and wisdom. Your interest in the situation has been demonstrated, and so has your impartiality.
"The fact you have powers is recognised. But it's also clear you will only use them in the last resort, and then only for constitutional - and not for political - reasons."
Australian Associated Press
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