When was the last time the Parliament (consisting of the monarch, a Senate, and a House of Representatives) had a session?
Graphic of the King

Parliamentary Education Office (peo.gov.au)
Description
A silhouette of the bust of the King. It says 'The King'.
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Good question!
The Australian Parliament consists of the King (represented by the Governor-General), the Senate and the House of Representatives. The King 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 about when the last time the monarch was physically present at the opening of a session of Parliament, this was 8 March 1977. Her Majesty Queen Elizabeth II attended the commencement of a new session on 2 other occasions, in 1954 and 1974.