Veterans who served as artillery gunners in Vietnam are at a reunion in Palmerston North to mark the 50th anniversary of New Zealand's involvement in the war.

Photo: SUPPLIED / Ministry Culture and Heritage

On this day in 1965, the first shot was fired by the 161 Battery of the 16th Field Regiment, Royal New Zealand Artillery.

To mark the occasion, veterans will be hosted by current members of the regiment and attend a memorial parade at Linton Camp near Palmerston North.

New Zealand became involved in the war to help South Vietnam and the United States try to halt the advance of communist North Vietnam.

The Prime Minister at the time, Keith Holyoake, told the nation in a radio broadcast why he thought this country should send troops.

"Communist terrorism must be halted. If a wider conflict in Southeast Asia is to be avoided then the lesson of history is clear: that we must stand firm in support of the small nations like South Vietnam."

There were 750 gunners who served in Vietnam between 1965 and 1971. Four were killed and one died of his wounds. Many others were wounded.

The 161 Battery was involved in 17 major operations, including the Battle of Long Tan in 1966, the Tet Offensive and Operations Coral and Balmoral in 1968. It was withdrawn in May 1971.

Photo: 123RF

Ian Barnes was 18 when he went to Vietnam to serve with 161 Battery.

"The fire control officer in the field would call for fire support. One gun would adjust to that support and then all six guns would open up and would give whatever fire support they required. I think the largest one we did was 100 rounds fire for effect from six guns."

Photo: AAP / AUSTRALIAN WAR MEMORIAL / EKT / 69 / 0015 / VN

Mr Barnes remembers Mr Holyoake visiting the troops.

"We were told to take all of our dirty clothes off and we got given brand new army boots and pants and shirts and hats and we stood there and were introduced to him, and when he left we were told to take them all back off again, hand them in and put our dirty stuff back on."

Kingi Tauroa of Ngapuhi was one of the first New Zealanders sent to Vietnam. He was 23 at the time.

Mr Tauroa describes jungle warfare as frightening.

"It is all damn guesswork you know, and the jungle is so damn thick and you can't see the enemy until you have made contact. The enemy mixed with the good guys (locals) and you can't identify anyone until later on when you realise that the enemy had been firing their guns from the very place you went through previously."

Another member of 161 Battery was John Barrett. He went overseas in 1968.

He says New Zealand troops did things differently from their American counterparts.

"The Americans would mostly go out, spend the day, hop on helicopters and come back again (to base). But we would patrol so that the Vietcong never really knew where we were or where we would pop up. We fought them in the same manner they fought so we were very effective in what we did."

Mr Barnes said, on returning home, all Vietnam veterans were hurt by the lack of recognition and in some cases the contempt with which they were received.

"We arrived home and we had to parade down Queen Street (Auckland) in vehicles and have the indignity of red paint and tomatoes thrown at us and we had to sit there and take it.

"We were attacked by the public and not only that - the RSA didn't want us, I mean they didn't see Vietnam as being a war."

Official recognition of the service given by the 3000 New Zealanders who served in Vietnam in the artillery, infantry and airforce did not happen until 2008.

Today, veterans of 161 Battery were welcomed with a powhiri at Linton Camp. This afternoon veterans will parade and a memorial plaque recognising those who lost their lives will be unveiled.

There will be a dinner tonight and a memorial service tomorrow.