Hundreds of people have turned out to commemorate the battle of Long Tan with a service at the Australian War Memorial, and another on ANZAC Parade in Canberra.

In the lead-up to the early-morning stand-to service, which is similar to a dawn service, names of the 521 Australians killed in the Vietnam War were projected onto the building's exterior.

Military cadets from the Australian Defence Force Academy and the Royal Military College - Duntroon also read out their names.

Veterans of the conflict were amongst those gathered. ( ABC News: Georgia Hitch )

A National Service was also held at the Vietnam War Memorial on Anzac Parade.

The Battle of Long Tan was the single largest loss of Australian life during the conflict, and began after a company of 108 men was ambushed at the Long Tan rubber plantation.

Eighteen Australians were killed in the battle and 24 were wounded, along with almost 250 Viet Cong soldiers.

Governor-General Sir Peter Cosgrove delivered the commemorative address. ( ABC News: Georgia Hitch )

Governor-General Sir Peter Cosgrove, himself a veteran of the Vietnam War, addressed both crowds.

He said Vietnam veterans were unique among Australia's returned military personnel, and the day was a chance to pay tribute to all those who served in the conflict.

"I think I'm entitled to say we're a funny mob, perhaps in some ways a bit weird, certainly we're different," he said.

"Not many returned veterans in wars before or since were sometimes booed, or occasionally even reviled by their own countrymen and women.

"Many Vietnam veterans felt alienated by the wider community from which they sprang and in many cases by the government which sent them and even most regrettably by the ex-service organisations which did not seem to embrace them."

The ceremony was accompanied by aircraft flyovers. ( ABC News: Greg Nelson )

The War Memorial's director, Brendan Nelson, said the battle of Long Tan encapsulated the struggle and sacrifice of the Vietnam War.

"Every war, every conflict, has an operation, a battle which captured the public imagination - the most dramatic battle, and costly, in which Australia was involved during the course of the Vietnam War was the battle of Long Tan," he said.

"It's become a battle which has come to symbolise the Vietnam War, and the legacy from ANZAC which was carried by those young Australians.

Dr Nelson also said he was "flabbergasted" by the Vietnamese Government's last minute decision to substantially scale-back commemorative plans at Long Tan.

"It's of course the veterans and their families who are on a pilgrimage to Long tan on the 50th anniversary for whom we feel the greatest sympathies," he said.