Australia Joining World War I In 1914, Australia joined the First World War. Although it was seen as a European war, the Australia government decided that Australia should support its 'Mother Country', Britain. The prime-minister at the time, Joseph Cook, stated Australia's position : "Whatever happens, Australia is a part of the Empire, right to the full. When the Empire is at war, Australia is at war." Many Australians objected to the country's involvement in the war, but the majority of the population agreed with the government's decision. Australia joined the war for many reasons, but two main reasons were : Australia (as a counr