The last New Zealand Army troops who took part in the Vietnam War flew home 47 years ago this month to a country that for the first time failed to put out a welcome-back mat for soldiers who had fought, killed and died in a foreign war.

The bitterly controversial conflict divided the nation and Vietnam veterans flew in at dead of night, were told to take off their uniforms and advised not to tell people where they had been.

The last group of 17 soldiers to leave Vietnam on December 19, 1972 ended the most shameful chapter of New Zealand's eight-and-a-half-year military commitment to the war.

David Barber Two Cambodian boy soldiers trained by NZ and US troops in Vietnam, nicknamed "Trash Can" and "Herman" by their American instructors. They are wearing cast-off US fatigue uniforms.

They were members of a training team that had secretly trained Cambodian boy soldiers as young as nine, 10 and 11 until the government ordered a halt after I revealed it four months earlier when reporting for the now defunct New Zealand Press Association.

The New Zealanders were working with a squad of 120 American army instructors established to help Cambodia, which was under increasing attack from the communist Khmer Rouge and the North Vietnamese Army. They had put about 2000 Cambodian recruits through a 12-week training course since the previous March.

Although the legal minimum age for service in the Cambodian army was 18, American instructors told me that about 100 recruits in the 500-strong battalion then being trained were under 15.

Supplied NZPA correspondent David Barber's US Department of Defense Certificate of Identity. Barber was NZPA's South-east Asia correspondent in 1970-73.

Medical orderlies said many had not reached puberty. Instructors said some were 10 and 11 and they had trained boys of nine. It was known that some were drafted from orphanages and one American told me: "The kids make good trainees. They are keener than most of the others because they think it's a game."

A sergeant said it "breaks me up" when they go on night manoeuvres at the end of the training – "… you know, they're still afraid of the dark".

The Americans had no illusions about the potential fate of the trainees when they went home to face a battle-hardened enemy. One said he had heard that two of the four battalions he helped train were wiped out within two weeks.

New Zealand was a reluctant partner in the training course at Dong Ba Thin, near Cam Ranh Bay. The last combat troops were withdrawn on December 9, 1971 after infantrymen had served with Australians in the Anzac base camp at Nui Dat for more than six years. As Washington's allies withdrew, the US pressured them to help Vietnam's increasingly beleaguered neighbour Cambodia.

"Trash Can" with rifle at the ready.

I stumbled upon the boy soldiers on a routine walk around the camp, struck by their size and the cast-off US steel helmets and fatigue uniforms, with rolled-up trousers and jackets down to their knees, that threatened to swallow them.

Defence officials had not disclosed their presence to the government and the hapless Defence Minister Allan McCready, who was shielded from the youngsters when he visited Dong Ba Thin, denied my story when it was published. Even after being corrected, he claimed that the number trained by New Zealanders was insignificant – "about 10".

Staff photographer Forty-six "boy soldiers" were sent home after Prime Minister Jack Marshall's Cabinet ordered training of under-age Cambodians to stop.

Strangely, the truth was still being denied 38 years later in the Ministry of Culture and Heritage's official history of New Zealand's involvement in Vietnam. War historian Ian McGibbon said only that "some were younger than 16".

But he admitted that 46 "boy soldiers" were sent home after Prime Minister Jack Marshall's Cabinet ordered training of under-age Cambodians to stop.

McGibbon claimed my story was "much to the team's anger" and reported "dire threats" to my well-being should I return to Dong Ba Thin.

The team's leader, Major John Daniell, however, had been clearly unhappy with the situation and told me frankly at the time: "If I could have stopped you seeing this, I would have done. I haven't been able to tell my wife in letters home about it."

. Norman Kirk ordered an end to all New Zealand involvement in Indo-China within three days of taking power after the November 1972 election.

The team was withdrawn after Labour leader Norman Kirk ordered an end to all New Zealand involvement in Indo-China within three days of taking power after the November election.

It concluded New Zealand's longest and most controversial military engagement of the 20th century, begun in June 1964 when Keith Holyoake's National government sent a group of non-combatant army engineers.

McGibbon claimed that the morale of New Zealand troops had remained "consistently high" and were aware that "their welfare was being adequately cared for" throughout.

In writing his 2010 account, however, he did not talk to any of the New Zealand Press Association correspondents who reported the war from 1965 to 1975.

In this correspondent's experience, the government maintained throughout at best a parsimonious and half-hearted commitment of support for the troops it sent. On every visit I made between January 1970 and December 1972, the most senior officers never failed to brief me in detail on complaints that went well beyond the expected whinges of troops at war.

Alone among the allies, the New Zealanders paid income tax and this was still a bitter issue with vets in 2008 when Helen Clark's government made a long-overdue acknowledgement to the more than 3000 New Zealanders who served in Vietnam, and honoured the 37 who died and 187 wounded.

"The Crown extends to New Zealand Vietnam veterans and their families an apology for the manner in which their loyal service in the name of New Zealand was not recognised in the way it should have been…" Clark told Parliament in May 2008 before the vets' first welcome-home parade through the streets of Wellington.

They had been denied a cost of living increase awarded to fellow defence personnel and all other public servants at home. They had their overseas allowances cut by 43 per cent in May 1971 after an irrelevant devaluation of the Vietnamese piaster and this was repeated for a handful of officers and men remaining at the end of 1972.

Senior officers told me that penny-pinching cost-cutting forced Kiwi troops to beg, borrow or steal from the lavishly-equipped Americans everything from basics like pumps, generators and vehicles to comforts such as water coolers, refrigerators and movies.

"We've become the biggest bludgers of the Vietnam War," one soldier told me. "We've had to."

David Barber covered the Vietnam War as the New Zealand Press Association's South-east Asia correspondent in 1970-73.