National Service Act 1964

The National Service Act 1964, was an Australian federal law, passed on 24 November 1964, which required 20-year-old males to serve in the Army for a period of twenty-four months of continuous service (reduced to eighteen months in 1971) followed by three years in the Reserve. The Defence Act was amended in May 1965 to provide that conscripts could be obliged to serve overseas, and in March 1966 Prime Minister Harold Holt announced that National Servicemen would be sent to Vietnam to fight in units of the Australian Regular Army.

On 5 November 1964 Cabinet decided to introduce a compulsory selective National Service scheme. In announcing this decision to Parliament, Prime Minister Robert Menzies referred to 'aggressive Communism', developments in Asia such as 'recent Indonesian policies and actions' and a 'deterioration in our strategic position' as being influential in the decision being reached (see Parliamentary Debates, House of Representatives, 25th Parliament, 1st Session, pp. 2517–2724). The Government had concluded that Australia had inadequate defence manpower and aimed to increase the strength of the Army to 33,000 by the end of 1966 by introducing national service.

Between 1965 and December 1972 over 800,000 men registered for National Service. Some 63,000 were conscripted and over 19,000 served in Vietnam. Although registration was compulsory, a process of selection by ballot determined who would be called up. Two ballots were conducted each year. The ballots selected several dates in the selected period and all males with corresponding birthdays were called up for national service. The ballot was conducted using a lottery barrel and marbles representing birthdays.

Conscription ended as one of the first acts of the newly elected Whitlam Labor Government in December 1972.