"In 1969, public support for the Vietnam War was declining. A Gallup Poll found that 55 per cent favoured bringing Australian troops home, and less than half wanted them to stay. All subsequent polls showed that a majority favoured bringing the troops home. In October 1969, during the federal election campaign, Opposition leader Gough Whitlam committed to the withdrawal of all Australian troops from Vietnam after June 1970 if the Labor Party was elected.
Universities around Australia became focal points for protest against the Vietnam War. From the mid-1960s to the early 1970s, Monash University in Melbourne, for example, became one of the key centres of student radicalism and protest in Australia. It was the site of many mass student demonstrations, blockades, sit-ins and the ceremonial burning of draft cards.
According to Australian Government Cabinet documents, in 1970 the Liberal Government was worried about the increasing level of conscientious objections and outright opposition to National Service. There was also concern about the sometimes heavy-handed approach of the police towards protesters and the number of young men who were ending up in the criminal justice system as a result.
Wikipedia, 'Conscription in Australia', http://en.wikipedia.org/wiki/Conscription_in_Australia