An Australian special forces soldier is under investigation for cutting off the hand of a dead Taliban soldier in a raid in Afghanistan earlier this year.

According to a statement issued by the Australian Defence Force (ADF) on Friday, the Special Operations Task Force and Afghan National Security Forces were dispatched on a raid targeting "an insurgent commander" operating in Uruzgan province.

Four Taliban fighters were killed in the raid, and an Australian solider is claimed to have cut off the hand of one of them for fingerprinting.

Australian troops are ordered to take eye scans and fingerprint all Taliban fighters killed for identification.

Australian broadcaster ABC reports that in the weeks leading up to the incident, an investigator from the Australian Defence Force Investigative Service (ADFIS) told troops at Tarin Kot that if necessary, troops should sever the hands of soldiers for fingerprinting.

The order contravenes Article 15 of the First Geneva Convention, which bans the bodies of dead soldiers from being "despoiled".

Gen David Hurley, chief of the defence force, issued a statement on 8 May saying that an investigation was underway, but admitted the nature of the investigation only on Friday.

"Following the mission, an incident of potential misconduct was raised through the ADF's internal command chain," the statement said.

Australian defence Minister Stephen Smith said: "We both found it puzzling, unusual and concerning, so it's not the ordinary course of events that we would expect from the Australian Defence Force or from special forces, but this was a fierce fight, circumstances in extreme, and we don't want to rush to judgement.

"It's difficult for me to prejudge, but the available evidence suggests that what is essentially asserted occurred, we now have to try to work out what were the facts and circumstances associated with that."

The ADF declined to comment while the investigation into the incident was underway.

"The ADF also takes all reasonable steps to ensure its operations do not breach Afghan customs or cause offence by inadvertently disrespecting religious beliefs or norms," it added.

Australian troops have been stationed in Tarin Kot since 2005.

Australia has an estimated 1,500 troops in Afghanistan. The majority are stationed in Uruzgan, with the remainder in Kandahar and Kabul provinces.