Labour leader David Shearer knows first-hand the challenges faced in Afghanistan and says New Zealand troops are doing an amazing job there.

Mr Shearer worked in Afghanistan during his former career as a humanitarian worker and in 2002 was the United Nations' senior adviser to the assistance mission there.

"Unfortunately, Afghanistan generally is a very violent place and there is always the threat of danger - and, tragically, that's what's happened."

He said his heart and prayers went out to the families of the dead soldiers and to the injured.

Bamiyan province was "as good as it gets", thanks to the work New Zealand and its troops had done with local authorities and development specialists. The northeast, where the attack occurred, was "more troublesome" than other areas.

"Anywhere in Afghanistan there are these underlying tensions, there are groups that want to destabilise and undermine the efforts that we have made."

Going into such areas was part of the job for New Zealand soldiers, and the country should be proud of their efforts, he said.

But former Green MP Keith Locke said New Zealand's efforts in Bamiyan had changed from being a peacekeeping force in the main city to one engaging in "active war".

Since passing responsibility for security around Bamiyan city to local forces, the Provincial Reconstruction Team had been redirected to the northeast, Mr Locke said.

"The original mission was being a provincial reconstruction team, not a unit involved in the war in Afghanistan."

- © Fairfax NZ News