The retired regular army officer, who said his largely conscript force had fought just as well as professional soldiers, has welcomed the belated recognition of the heroism of many of the soldiers caught up in the Vietnamese ambush ahead of Thursday's 50th anniversary commemoration.

He, like many others, can't understand why the issue of awards and honours wasn't resolved decades ago.

"The politics of these things is disappointing; it does not reflect well on the system," he said.

The Canberran noted there had been three previous Long Tan awards inquiries before the one that recommended awards and upgraded awards for 10 men, including himself, last week.

"This overturned all of them," he said. "The last one [before this] was a non-event. I wondered what the hell I was there for. They didn't ask me any questions or anything."

He is looking forward to reconnecting with former friends and comrades, both living and dead, when thousands of Vietnam veterans from around the country converge on the Australian War Memorial.

"I'm laying a wreath," he said. "I've got photographs of the APC fellows who were killed [in Vietnam]. I want to personalise their sacrifice."

A lieutenant in the regular army in August 1966, Colonel Roberts lost one man from his small command during the dangerous journey across flooded creeks and through enemy infested territory to relieve then Major Harry Smith's force which was pinned down and outnumbered by at least 20 to one.

Corporal Peter Clements, a 21-year-old regular, was shot in the stomach while manning the .50 calibre machine gun on his APC. He died 10 days later.

"I saw an explosion in front of the carrier commanded by Corporal John Carter and a rubber tree came down," Colonel Roberts said.

"Ahead of the carrier I saw a very brave enemy soldier with what turned out to be a 57mm recoilless rifle [an anti-tank weapon] and another equally brave enemy reloading it. They fired again but the round struck the [fallen] rubber tree. Corporal Carter, whose .50 calibre machine gun had jammed, killed them with an Owen gun."

This was not the only APC to have problems.

"In the middle of the fighting the carrier commanded by Trooper Bill 'Boss' Smith, a national serviceman, suffered a jammed machine gun," he said.

"The driver, Fred Castledean, stood up in his seat and, exposed to enemy fire from the waist up, unscrewed the [gun barrel] and replaced it with a spare. Smith, equally exposed, carried out the necessary checks before resuming firing. Neither has been recognised for what they did."

Another who displayed great courage was Sergeant Noel Lowes, the soldier Colonel Roberts ordered to take the place of the mortally wounded Clements.

"Lowes slipped out the back of the APC and then, using the other carriers for cover, made his way about 100 metres to the machine Clements was in. He was almost shot by one of our own soldiers. Lowes was a very brave man and his run should not be forgotten."

Sergeant Ron Richards, who commanded the APCs carrying 2 Platoon, performed magnificently.

"He had passed just west of Delta Company, realised we weren't with him, did an about face and came back. Even when he got ahead of the action he was totally steady, reliable and composed."

Colonel Roberts would liked to see a unit citation for the small APC force but realises that under the military's protocols this will never happen.

"My men fought like heroes and I want their efforts to be remembered," he said.