Preparations are being made to repatriate the bodies of two New Zealand soldiers killed in action in Afghanistan's Bamyan province.

The attack on Saturday night (local time) left six other soldiers wounded with three in a serious condition.

Chief of Defence Force Lieutenant General Rhys Jones told a briefing in Auckland on Sunday that one of the soldiers was in an armoured vehicle hit by a rocket and the other was hit by a blast or fire from a rifle.

One died immediately and the other died in a helicopter while being evacuated.

The Defence Force was expected to release the names of the dead soldiers on Monday, after their next of kin had been given a chance to grieve.

It is hoped their bodies will be returned home next week, with the help of the Australian and British defence forces.

The New Zealand Provincial Reconstruction Team had gone to the aid of local security forces fighting suspected insurgents near a village south of Do Abe at about 7pm NZT on Saturday.

The insurgents moved into a building and the New Zealanders were asked to fire on the building and secure the area. They were attacked as they were moving to secure high ground.

Prime Minister John Key said three of the wounded soldiers were seriously injured but were in a stable condition and three suffered moderate injuries.

They were being treated in military hospitals.

"It's with enormous sadness that I acknowledge that these soldiers have paid the highest price," Mr Key said.

"This brings the total number of New Zealand soldiers who have lost their lives in Afghanistan to seven."

The attack came almost exactly two years to the day of New Zealand's first fatality in Afghanistan, when Lieutenant Tim O'Donnell was killed in an attack on his patrol in the same area on August 4, 2010.

Lt Gen Jones said there has been an increase in insurgent activity in the area during the past month.

The soldiers were three months into their deployment and they were experienced in operating in the area, Lt Gen Jones said.

Governor-General Sir Jerry Mateparae, a former chief of the NZDF, said the two soldiers who paid the ultimate sacrifice and the six injured were part of a team that had worked tirelessly and consistently to bring peace and stability to the province.

Defence Minister Jonathan Coleman has also offered his condolences to the families.

"Our thoughts are especially with the families of those who died, and the families of those who were wounded," Mr Coleman said.

"The work the NZDF undertake in this region is dangerous and they have been well trained to respond to these incidents."

Labour leader David Shearer said it was a real tragedy, particularly as the New Zealand operation in Afghanistan was winding down.

"These guys are doing their duty for the country. They have done a great job and our hearts are with the families," Mr Shearer told TVNZ.

Green Party co-leader Metiria Turei said her party's thoughts were with the families of all of the soldiers.

"Losing loved ones is always devastating, but it is especially so when they chose to selflessly work on the other side of the world in a community that has been devastated by war and terror," Ms Turei said.

"The provincial reconstruction team is supporting and working with communities in Afghanistan to rebuild and to reconstruct their homes and communities, and ultimately their lives."

New Zealand has previously announced its intention to withdraw from Bamyan in 2013, a year earlier than first intended.