Thanks for your question, Sylvia.
Although the Prime Minister has a very important and high-profile position, only sometimes do they have the last say. It really depends upon where, and in what capacity, the Prime Minister is speaking.
As the Leader of the Australian Government, the Prime Minister will have the last say in:
However, the Prime Minister is chosen by a vote of the members of the government and can only keep their job as long as they are a member of parliament and have the support of the government.
While the Prime Minister is often seen as the most important person in Parliament, their position is not mentioned in the Australian Constitution. Instead, the Prime Minister works according to practices and customs that developed over hundreds of years in the British Parliament and were then adopted by the Australian Parliament.
The Prime Minister is a member of the House of Representatives but does not have the final say in its meetings. It is the Speaker who manages the debates and the Prime Minister can only speak when called upon by the Speaker.
To make or change a law for Australia, all three parts of Parliament must agree. The House of Representatives has to agree—where the Prime Minister has a single vote—and the Senate has to agree—where the Prime Minister doesn’t get to vote at all—and then the Governor-General has the final say as to whether to provide Royal Assent—sign the bill into law—or to withhold assent.
As you can see, sometimes the Prime Minister does have the last say, but there are plenty of occasions where they do not!