First of all a republic is a state in which the supreme power resides in the body of citizens entitled to vote and is exercised by representatives chosen directly or indirectly but them
(Macquarie Dictionary). In a republic a head of state is a citizen of that country elected by fellow citizens. If birthright determines the head of state of a country then that country is a monarchy, which at the moment Australia is. Our head of state is currently the Queen, but the Governor-General, who is appointed by the federal government (does not need to be an Australian) represents her. We are a monarchy because of Britain’s colonisation of Australia in 1778. The British brought their way of life, culture and most importantly their way of government with them. This system of government has remained to this day. Becoming a republic would not mean that we would lose that history we have with Britain and that if we were to become a fully independent nation it would not severe ties. The Queen has also stated that this was an issue that should be left for Australians to decide.
The Queen made her point clear after her representative the Governor-General at the time, Sir John Kerr, dismissed the Prime Minister, Mr Gough Whitlam, and instead appointed Mr Malcolm Fraser to the title. This has become to be known as the Whitlam dismissal, and has become the most dramatic event in the history of the Australian federation. An unelected vice-regal representative removed a leader whose party had the majority of seats in the House of Representatives. The speaker from the House of Representatives wrote to the Queen. This is the letter her secretary sent back:
I am commanded by The Queen