The Australian Parliament consists of the Queen (represented by the Governor-General), the Senate and the House of Representatives. The Queen is rarely present at a parliamentary session, as it is the Governor-General who represents the monarch at the opening of a Parliament.
A session of Parliament commences on the first sitting day following a federal election or prorogation—the formal ending of a session—and concludes either by prorogation, dissolution or at the end of 3 years from the first meeting of the House.
If you are asking when the last time the Queen was physically present at the opening of a session of Parliament, this was 8 March 1977. Her Majesty Queen Elizabeth II has attended the commencement of a new session on 2 other occasions—1954 and 1974.