Queen Elizabeth II's correspondence on her role in the 1975 sacking of Australian prime minister Gough Whitlam will be released next week, it was announced Thursday, after a lengthy battle to make the documents public.

The British monarch's representative in Australia, governor-general John Kerr, sparked a constitutional crisis in 1975 when he dismissed Whitlam, the popular leader of the centre-left Labor party, three years after his election.

Australia's High Court ruled in May that more than 200 letters between the queen and Kerr over the controversial affair should be part of the public record after her representatives had successfully kept them secret for decades.

The National Archives of Australia said Thursday it would release the correspondence -- amounting to over 1,000 pages known as the "Palace Letters" -- on July 14 with no redactions.

Australia became independent from Britain in 1901 but Queen Elizabeth II is still head of state
Australia became independent from Britain in 1901 but Queen Elizabeth II is still head of state POOL / TOBY MELVILLE

"The National Archives has examined the records for public release under the provisions of the Archives Act 1983 and I have determined all items will be released in full," director-general David Fricker said.

Many of the 212 letters have attachments including newspaper clippings and other reports relating to Kerr's work as governor-general, Fricker added.

The letters could help show if the British government tried to influence events in its former colony and what role the queen, Prince Charles and top royal advisers may have played.

Local historian and Whitlam biographer Jennifer Hocking, who took the case to court in 2016, spent years arguing the texts were "extraordinarily significant historical documents" that should be made public, while the queen's representatives had argued the correspondence was private.

Australia became independent in 1901, but the queen is still head of state. A referendum on becoming a republic failed in 1999.