From 1964 until 1972, 20-year-old Australian men had to register for the national service scheme where, twice a year, a ballot was held to decide who would be called up.

If a man's birth date was randomly drawn from a barrel, two years of full-time service in the army beckoned, which from 1966 could also mean combat duties in Vietnam, according to the government's commemoration website.

Over the eight years of the scheme, more than 15,000 national servicemen served in Vietnam. Two hundred lost their lives.

Among the Whitlam ministry's first acts after it was sworn in was to release the seven men who were in jail for resisting the draft, Sydney University associate professor James Curran said.

The pending prosecutions for 350 other draft resisters were also dropped and conscription was ended in December 1972. Australia then withdrew its remaining military advisers from Vietnam.

"The lottery of death was abolished," associate professor Curran said. He is writing a book on the US alliance under Mr Whitlam, Unholy Fury, to be published next year.

Monash University associate professor in politics Paul Strangio said there is no doubt Whitlam's actions were a "powerful symbolic moment".

"It lifted an enormous millstone off a generation," he said.

But he and associate professor Curran cautioned that the issue of conscription was a complex one for Gough Whitlam and for Labor.

While public opposition to the Vietnam War and conscription built to a fever pitch in the late 1960s and early 1970s, there was little opposition in the early years of Australia's involvement in the conflict.

"Whitlam was always mindful of trying to navigate public opinion [on it]," associate professor Strangio said.

He said Australia had already begun disengaging from Vietnam under the Coalition. Liberal prime minister William McMahon withdrew Australia's combat troops at the end of 1971.

Associate professor Curran also pointed out that Mr Whitlam had broken with then Labor leader Arthur Calwell on the issue before the 1966 federal election.

Mr Calwell had wanted to bring home all conscripts from Vietnam and withdraw the remaining regulars in consultation with the United States. Mr Whitlam instead argued that if further Australian participation in Vietnam was needed, the regular army would be used, confusing Labor's public position.

"Whitlam had to walk that fine line between opposing the war, but also maintaining support for the US alliance," associate professor Curran said.