Fresh questions are being raised about New Zealand's elite SAS soldiers and their role in detaining prisoners and then handing them on to other forces who may have tortured them.

Metro magazine, published tomorrow, reveals three incidents - one in 2002 and two in 2010 - when the SAS took prisoners and handed them to other forces.

In May 2002 the SAS led a mission in the village of Bande Timur, 80km west of Kandahar.

According to Metro, it resulted in the deaths of at least three people, including a small child, and the arrest and torture of many others after the SAS handed 55 prisoners over to US forces.

"They beat us very badly in prison," one of the prisoners, Abdul Wahid, told Metro.

"They cut off our hair, and they shaved our beards and moustaches."

Others said they were bound and hooded while dogs rushed at them in a threatening manner, paraded naked in front of Americans, and one was said to have been beaten so severely that he couldn't move his hands or legs and ended up disabled and in a wheelchair.

The men were later released without charge.

New Zealand is a signatory to a number of international conventions, including the Geneva Convention, against torture and inhumane or degrading treatment of prisoners.

Under the conventions and the Defence Force's rules, New Zealand troops cannot transfer prisoners to another state unless they are satisfied they will not be tortured or treated inhumanely.

SAS soldiers are quoted by Metro expressing their displeasure at the treatment of the prisoners.

One climbed on a roof to see inside the US prison and said it "looked like Guantanamo Bay".

Metro also reveals details about two incidents last year; one where an SAS prisoner was handed to the Afghan National Army, who proposed to tie the man to a vehicle and drag him for over 100 kms of gravel road.

The SAS intervened and handed the prisoner to the Afghan Crisis Response Unit (CRU), who then passed him to the Afghan secret police, the National Directorate of Security (NDS); a British court has banned British forces from handing over prisoners to the NDS in Kabul.

And on Christmas Eve incident in Kabul, an SAS raid resulted in the deaths of two men. The SAS gave its prisoners to the NDS.

Prime Minister John Key said last August that when the SAS handed someone they had detained to other units, they made sure that person would not be tortured.

It worked alongside the CRU and was not the detaining force, he said.

But Metro quotes a senior Afghan special forces officer saying that the SAS is "very, very involved" in taking prisoners.

Defence Minister Wayne Mapp told the Herald that the Defence Force has been "repeatedly assured by the SAS that it was the Afghan Crisis Response Unit that had taken detainees on various missions since their deployment in September 2009".

On recent SAS deployments, a legal officer has been assigned to the mission, he said.

"On my visit to Afghanistan in August 2010, I formally raised the issue of detainees with General David Petraeus, the ISAF (Nato force) commander. He assured me that ISAF Command had put substantial effort into this issue, and was working closely with the Government of Afghanistan to ensure that it has a full understanding of its legal obligations.

"In the event of any New Zealand Defence forces taking a detainee, they have detailed obligations under the law of armed conflict as to how that person will be treated."

Dr Mapp has previously told a parliamentary select committee that the Red Cross would advise New Zealand if prisoners captured by the SAS were being mistreated by Afghan forces, but Metro quotes a Red Cross official saying there is no such agreement with the New Zealand Government.

Last year Dr Mapp said there was a possibility that prisoners from the SAS were passed on to the NDS, and he could not rule out the possibility that they may have been tortured.

He ordered an inquiry, which is yet to report back.