The former soldier issued a call to arms to his fellow Vietnam veterans to share their support for those who had fought in Afghanistan, who were now forced to watch the country collapse again after the Taliban seized control.

"It has been 50 years since Australia withdrew its troops from South Vietnam ... but the war continued for another four years before America withdrew its troops and returned home. Then North Vietnam invaded the South, and took over the whole country," he recalled.

"The whole country of Vietnam was then united again, as it was before the war started ... the same thing is happening in Afghanistan at the moment, and I ask you all ... let us support our Afghan veterans, and get behind them, we Vietnam veterans know what they are going through because the same thing happened to us in Vietnam 50 years ago."

Sharing his message at a ceremony in Launceston, Tasmania, to mark Vietnam Veterans' Day on Wednesday, Mr Wise spoke of how family support kept many veterans alive after they returned from the war.

And it was that kind of support that the community needed to provide to Afghanistan veterans, he said.

"We survived the conflict, but on our return to Australia we had difficulty in surviving civilian life, and I know the same applies for our veterans today that are coming back from distant conflicts - Iraq, Afghanistan, Timor," he said.

"We have been through it, us Vietnam veterans, and we understand and we feel for you.

"We craved for the support and understanding of the community at a time when only we as veterans understood what we had experienced."

Over the past five decades, that support had only increased, and Launceston RSL secretary Pete Williams said more changes were on the horizon when it came to veteran support programs in Tasmania.

An Afghanistan veteran himself, he spent six-and-half-months in the country in 2013, working with the US army in Kandahar on a series of projects aimed at increasing the capacity of the Afghan national army and the country's police forces.

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Mr Williams said from his experience he was "not surprised" by what was now happening in Afghanistan.

"I would put it down to not only poor leadership, but corruption within the Afghan government and within the army," he said.

"Even while I was there we had issues where the Afghan army guys weren't being paid and the money was being skimmed off by their commanders.

"Quite frankly, the Afghan army when I was there was very capable ... and they were successful in pushing the Taliban back, but over the years their capacity has been worn away, through mismanagement and all that, and it's like any army, it doesn't matter how many good soldiers you have got unless you have leaders saying 'follow me' you are not going to win a war."

While August 18 was known as Vietnam Veterans' Day, it officially marked the anniversary of the Battle of Long Tan.

Wednesday also marked 55 years since that battle by the men of D Company, 6th Battalion, Royal Australian Regiment.

On that day, 108 Australian and New Zealand soldiers fought a pitched battle against more than 2000 North Vietnamese and Viet Cong troops, with 18 Australians losing their lives and 24 wounded.

It was part of a war that lasted nearly two decades - making it the longest 20th century conflict involving Australian soldiers.

More than 60,000 Australians served during the Vietnam War, with more than 500 Australians killed, including 16 Tasmanians.

But it was not only the army that was involved.

Former Royal Australian Air Force flight lieutenant John Chenery was in the air force during the Vietnam war and provided support to the troops on the ground.

While the war itself was controversial, Mr Chenery said he remained proud of what he had contributed during his career with the RAAF.

"Most of the work I did in the air force was humanitarian work - cyclone relief, flood relief, search and rescue - so you think 'OK, I did something for our country, and for humanity', and I feel good about it," he said.

Fellow ex-RAAF officer David Moles, who also served with the army in the Malayan and Indonesian confrontations, served in South Vietnam during his career with the air force.

When he returned home from Vietnam, he continued his RAAF career, but witnessed the public mistreatment of army veterans returning from the same war.

"It was disgusting ... soldiers don't pick where they get sent," he said.