New Zealand's 50 Special Air Service (SAS) troops have returned from fighting remnants of the Taleban in Afghanistan and there are no immediate plans for them to return, Defence Minister Phil Goff said today.

The 50 troops flew back into New Zealand early this morning.

Another 120 New Zealand troops involved in a provincial reconstruction project, remain in Afghanistan.

Mr Goff said the third rotation of SAS troops had played an important role through reconnaissance work and "direct action missions".

"Their presence, together with other international forces, has been critical both to constrain the influence of Al Qaeda and Taleban elements and to allow nation building and reconstruction to take place."

A spokesman for Mr Goff said no further SAS deployment was currently planned.

The return of the SAS troops follows comments yesterday by Prime Minister Helen Clark that New Zealand was unlikely to boost its military commitment in Afghanistan.

The United States plans to pull 4000 troops out of Afghanistan early next year, and the British government has been trying to pull together a coalition counter-insurgency force to fill the gap.

Helen Clark said yesterday defence officials had been approached by their British counterparts around the time of the election, but no official talks had yet been held.

Troops working on provincial reconstruction are due to finish in September next year and Helen Clark has said it will be up to Cabinet as to whether they continue past that date.

New Zealand was open to its provincial reconstruction team being transferred to a Nato-led force, provided there was sufficient back up.

However it was highly unlikely it would boost its military commitment beyond the level it had been at in recent times.

Green MP Keith Locke said today the Prime Minister's comments, coupled with the return of the SAS troops, signalled it was unlikely New Zealand would join the proposed British-led counter-insurgency force.

But he said the Government needed to make absolutely clear whether that was the case.

Mr Locke said the return of the SAS troops was positive as they had been involved in a US-led campaign that employed highly questionable tactics.

Reports have suggested troops involved in counter-insurgency operations in Afghanistan were trigger-happy and treated prisoners poorly.

"New Zealand troops shouldn't be involved in those kind of operations under either the United States or the British," he said.

"It's a dirty war and should not be the role New Zealand is projecting in Afghanistan and the world."

He also said the operation appeared to be failing, with casualties and the level of insurgent activity growing despite a four-year campaign.

Foreign Affairs Minister Winston Peters will meet Britain's defence minister during a visit to Britain after attending a meeting of Commonwealth foreign ministers in Malta this week.

Helen Clark said Mr Peters could register any British request for New Zealand to join a new force.

Mr Peters' position outside the Government would not affect the meeting, she said.