The service of thousands of Australian men who took over the national service in the 1950s, 60s and early 70s was commemorated at the Australian War Memorial on Friday.
Foreign Affairs Minister Marise Payne joined the veterans and their families in a wreath-laying ceremony.
The commemoration also featured a generous and significant donation from a veteran of the Vietnam War.
Allen May donated his beloved medals to the Australian War Memorial.
"They are sitting there, I told them that if they died before going somewhere, they would simply sit there," he told SBS News.
Between 1951 and 1959, 18-year-old men were required to register for national service. More than 220,000 underwent six months of mandatory military training in the military, navy or air force.
The men had to choose which branch they served.
In 1964, a National Service Scheme was reintroduced, with the government granting new powers to send national soldiers abroad.
This was significant, since the Australian soldiers were involved in the Vietnam War.
All 20-year-old men were required to register with the Department of Labor and National Service, with selected recruits on a random birthday ballot.
Exemptions were granted to Aboriginal and Torres Strait Islander people, medically unfit students and theology students.
Under the scheme, which would last until 1972, nearly 64,000 young people were recruited to serve two full-time years in the military.
More than 15,000 of the conscripts served in Vietnam.
Mr. May was among them. He was 21 years old when he was recruited in 1965.
After arriving in Vietnam he became an advanced explorer. Historians believe that he fired the first shots in what is known as the Battle of Long Tan.
Ms. Payne paid tribute to the recruits and those who volunteered to serve.
"The men we spoke of today served our nation in times of great uncertainty and strategic danger," he said.
In addition to his medals, Mr. May has donated letters he wrote to his mother from the front line.
The May May medals will be permanently on display at the Long Tan exhibition of the Australian War Memorial.
He hopes that they will help Australians understand the contribution he and other national military made to the history of the country.
The Director of the Australian War Memorial, Brendan Nelson, said it was a huge gesture.
"I can not adequately convey to Australians the emotional significance of those medals for that man, and then the generosity of his gift of giving them to us, the Australians."