Updated

A historian is appealing a court ruling that continued to keep secret letters that might reveal what Queen Elizabeth II knew of her representative's plan to dismiss Australia's government more than 40 years ago.

The National Archives of Australia has categorized the correspondence between the British monarch, who is also Australia's constitutional head of state, and Governor-General Sir John Kerr as "personal" and the letters might therefore never become public.

The Federal Court last month agreed the letters were "personal' and not state records, dismissing Monash University historian Jenny Hocking's application to have them made public.

Hocking said Tuesday she lodged an appeal to the full bench of the Federal Court.