A secret SAS mission to take out Taleban fighters who killed a New Zealand soldier was needed to "send a message" to insurgents, the father of a wounded soldier has claimed.

Lieutenant Tim O'Donnell was killed in August in an ambush in a mountainous region of Bamiyan province in Afghanistan - the first New Zealand soldier in a decade to die in combat.

A counterattack involving the SAS took place two weeks later. Last night, the Defence Force said nine insurgents were killed, not 12 as earlier reported.

Steve Baker, father of Matthew Baker - a soldier who was wounded in the attack which killed Lieutenant O'Donnell - told Newstalk ZB the attack was necessary.

"I think those that commit those acts have to be held responsible, maybe have to send a message that if they're going to do these attacks that there's going to be consequences," he said.

However, SAS Association President David Maloney denied it was a revenge attack.

"I doubt whether they had that specific information but they had some general information as to the Taleban leaders that were crossing the border so they would mount an operation specifically to deal with a group.

"If a soldier has revenge, it then tends to cloud judgements and it is really opportunity to sort out the enemy that comes up that you're focused on."

Defence Minister Wayne Mapp reiterated his claim the SAS soldiers acted professionally and were not motivated by revenge.

"There was no aspect of retaliation. That's not how we conduct operations. We act on intelligence. The one thing we don't want to do is sit there waiting for people to attack us."

He said the mission was part of the SAS duty to secure the Bamiyan province against the Taleban insurgency.

Lieutenant O'Donnell died on August 4 while on patrol in northeast Bamiyan. The Taleban fighters who attacked the convoy had come from neighbouring Baghlan province.

On August 22, the International Security Assistance Force (ISAF), as the Nato force is known, led an early-morning raid in Talah wa Barfak District, Baghlan.

Dr Mapp confirmed New Zealand forces were part of the mission, but it was not clear how many were involved or whether they shot any insurgents.

"We have special forces to be able to undertake military operations - that is part of their overall remit."

The district's governor initially said there were eight civilian casualties, and a Nato investigation later revealed a malfunctioning gunsight on a coalition helicopter that had resulted in errant shots hitting a building. The building was struck mistakenly, but was previously used as a base for insurgent operations.

US Air Force Brigadier General Timothy M. Zadalis said at the time that the coalition regretted "any possible civilian loss of life or injury".

Dr Mapp said investigations had found that no civilians were killed in the strike. It was not unusual for the SAS to move out of Kabul, where they were usually based.

"It is in the remit of the special forces to be able to undertake operations at the direction of ISAF and Nato, and in this case particularly to protect our people."

Lieutenant O'Donnell was part of the provincial reconstruction team of about 140 New Zealand troops who do aid work and military patrols in Bamiyan province. The team is due to withdraw by 2014.

Recently, New Zealand forces in Bamiyan were beefed up with five extra light armoured vehicles and more infantry.

"The northeast is the most demanding part of our area of operations and requires a higher level of capability," the Commander of Joint Forces, Air Vice Marshal Peter Stockwell, said last week. "This area of the province was where Lieutenant Tim O'Donnell was killed last year, and it is where we have most often come into contact with armed insurgents."

Green Party defence spokesman Keith Locke said the SAS should not be involved in the war, regardless of whether it was in Kabul or Baghlan.

"We would rather that they weren't there. This ongoing, apparently unwinnable war is not one we should be involved in."

The 70 SAS troops were due to pull out of Afghanistan last month, but the Government approved a smaller group staying on for a further year.

- with Newstalk ZB