Australia's national service scheme was introduced in 1964, and although it was not brought in to enable Australia's participation in the Vietnam War, large numbers of people believed this to have been the case. Opposition to the scheme, which grew increasingly widespread once national servicemen began to be sent to Vietnam, became the catalyst for broader opposition to the war.
During the early years of the war, when Australia's contribution was limited to members of the regular Army, the public were largely disinterested. Only when the commitment increased to include national servicemen, and particularly after the 1968 Tet Offensive, did widespread opposition to Australia's participation in the war develop. After 1968 both the United States and Australia began to withdraw combat troops from Vietnam, the period of major protest in Australia – the moratorium marches of the early 1970s – occurred at a time when Australia was disengaging from the war.
Anti-war groups existed in Australia long before the war became widely unpopular. Organisations such as Save Our Sons and Youth Campaign Against Conscription were at the vanguard of the protest movement fighting, in the early days, a lonely campaign against Australia's involvement in a war that had yet to attract widespread opposition.