Australia and the Vietnam War
Australia had supported the French-sponsored government of Emperor Bao Dai in Vietnam.
In 1954 the Viet Minh defeated the French, ending the French presence in the region. (The Viet Minh was formed in China in May 1941 by Ho Chi Minh)
In 1955 The US took over from the French in aiding the Saigon Government.
In 1957 The Australian Prime Minister Menzies reaffirms support to South Vietnam’s President Ngo Dinh Diem.
The war then happened, and Australia followed up with its commitment of support, along with other countries.
The Vietnam War 1962–75
South Vietnam was backed by anti-communist countries and members of the South East Asia Treaty Organization (SEATO) which included the United States, South Korea, Australia, the Philippines, New Zealand, Thailand, Khmer Republic, Kingdom of Laos and Taiwan.
North Vietnam was backed by the communist allies which included People’s Republic of China, Soviet Union, Pathet Lao, Khmer Rouge and North Korea.
Vietnam War Time Line for Australia: http://www.vvaa.org.au/calendar.htm