Officially known as the Battles of Fire Support Bases Coral and Balmoral, the firefight erupted 54 years ago, eventually claiming 26 Australian lives, including former Bendigo resident Bevan Maxwell Trimble.

Bendigo's solemn service was led by Graham Christie, a Vietnam veteran who remains dedicated to preserving the memory and service of his countrymen and women.

Light, misty rain fell throughout the ceremony, as those who served and their families and friends paid homage to all servicemen and women, but especially those from the Coral Balmoral battle.

"The Vietnam War tested the moral fibre of our nation - but it never weakened the discipline nor the courage of our soldiers, our sailors, our airmen or our nurses," Mr Christie said.

"Our duty is to recognise the welfare of all our servicemen and women, an issue which has never been more critical than today.

"The conscience of the Royal Commission and every community demands that we listen, encourage and offer support to all our veterans, ensuring that their duty, their service to Australia is recognised, respected and remembered."

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As 22-year-old conscripted National Service member, Mr Christie was a Lance Corporal serving with 104 Signal Squadron, when he and his fellow soldiers were sent to a series of rubber plantations and rolling grasslands north of South Vietnam's capital Saigon.

They had earlier set up two fire support bases - Coral and Balmoral, about four kilometres apart in an area they were not familiar with.

Tragically, they did not understand they had landed and set up base close to a North Vietnamese underground bunker system.

The Coral base was later found to be adjacent to a large hidden enemy bunker system, providing the enemy with a huge consumate advantage as they observed the entire deployment, perimeters, signals, artillery emplacements, giving them the ultimate advantage.

On May 11, a torrential downpour rolled in, and many soldiers had not had time to properly dig in midst the horrendous conditions. In the early hours of the following morning, North Vietnamese forces began their assault by firing hundreds of mortars and rocket propelled grenades on Australian and New Zealand positions little larger than a cricket ground.

The barrage was followed by an all our assault by the North Vietnamese soldiers, who charged in what Mr Christie has described as "an incredibly frightening human wave onslaught of literally thousands of the enemy".

In his submission to the federal government inquiry into unit recognition for service at the Battles of Fire Support Bases Coral and Balmoral convened in 2017, Mr Christie wrote:

"Our fears were quickly realised in the early hours after midnight of Sunday 13 May - when the ferocity of a deadly saturation barrage of hundreds of mortars and rocket propelled grenades suddenly impacted accurately on our small area - crunching explosions that rattled your very being and frightened you beyond belief to the point that you knew that your own death was inevitable."

Mr Christie said the ferocious attacks from the enemy were to be the pattern for the next 25 days of heavy conflict and carnage, in the heat, mud and rain.

"It challenged our resolute defiance to defend, which over time inspired resilience and many acts of selfless heroism."

The battle last 26 days, and ultimately saved Saigon.

"But the devastating carnage created such gruesome images that will remain in the psyche of every soldier forever," Mr Christie said.

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In his oral submission to the inquiry, retired Colonel Gerry McCormack said sleep and rest were luxuries enjoyed by the few during the battle.

"Every time you wake up you expect something to happen - sustained expected combat. You cannot wind down because there's nowhere that feels safe."

Towards the conclusion of Friday's ceremony, the names of the 26 Australian Diggers who made the supreme sacrifice in the muddy, bloodied battle were read aloud, each brave soldier's name followed by the ringing of a bell.

The first to be named was Private Bevan Maxwell Trimble, a Bendigo local who was killed on the first night of the battle, defending his nation in a war fought far from home.

None of those lost were older than 28, one of them still a teen. All of them, including 21-year-old Gunner Ian James Scott, from Camperdown, taken far too soon.

- PETER KENNEDY