Prime Minister John Key has confirmed New Zealand SAS troops are in Kabul, Afghanistan.

The location of New Zealand's secretive Special Air Service (SAS) troops was revealed by Norway's defence chief.

The New Zealand Government has a policy not to publicly divulge their whereabouts.

Mr Key previously announced the SAS had left New Zealand and today he confirmed they were in Kabul.

It was a "long-standing" practice not to reveal the location of the SAS.

"The Norwegians have publicly said that they're replacing them in Kabul, I'm not going to deny that's not the case, that is."

The rationale for not revealing the SAS's location was often claimed to be safety.

Today, Mr Key said he did not believe the SAS were in any danger because their location was known.

The Government was not trying to be "obstinate" and maybe it was time to review the policy, he said.

He refused to discuss what the SAS would be doing in Kabul.

General Sverre Diesen told Oslo-based newspaper VG the SAS would replace a Norwegian special forces contingent that had been based at Kabul.

The Norwegians had been involved in the arrest of "several wanted insurgent leaders responsible for planning and running suicide attacks against targets in the Kabul region", Gen Diesen said.

The SAS would "take over" from the Norwegians, he said.

The VG story is not the first time details of an SAS deployment have been reported overseas while the New Zealand Government remained silent.

In 2002 Prime Minister Helen Clark was forced to confirm the SAS were in Afghanistan after the White House website revealed their presence.

- NZPA