The behaviour of elite special forces soldiers is being closely scrutinised by a former spy boss to determine whether cultural problems persist inside their secretive military community.

Concerns about the conduct of Australia's SAS and commando regiments during the war in Afghanistan have emerged over the past few years, with allegations of unlawful killings and other serious criminal acts which were covered up.

The behaviour of elite special forces soldiers is set to face scrutiny. ( Supplied: Defence Force )

In a sign that Defence fears it may be exposed to serious scrutiny over what has occurred, retired intelligence figure David Irvine has begun the second known high-powered investigation into special forces since the end of combat operations in the Middle East.

The first is an inquiry by the Inspector General of the Australian Defence Force (IGADF) launched in 2016, probing conduct of special forces during the 12-year Afghan conflict.

The IGADF inquiry was prompted in part after a 2016 review of special forces by a Canberra academic uncovered unverifiable allegations of unsanctioned and illegal application of violence on operations.

Now the ABC can reveal Mr Irvine has been asked to examine what improvements have been made within the Special Air Services Regiment and commando regiments since problems began to be identified during the war in Afghanistan.

David Irvine, pictured here in 2014, will spearhead the investigation. ( AAP: Lukas Coch )

In a statement the Department of Defence said "Army has engaged David Irvine to conduct an independent assessment of reform measures implemented within Special Operations Command".

"Reviews within Army are common practice for commanders to gain an understanding of the overall effectiveness of their command and identify areas of excellence and improvement."

The Defence Department said "Special Operations Command has implemented a number of cultural and governance reforms since 2015" and Mr Irvine's independent review is "a separate activity and does not affect the IGADF Afghanistan inquiry".

It's not clear when the review is expected to be finalised and released, but the ABC has been told it is likely to be coordinated with the release later this year of the IGADF's inquiry.

When the IGADF inquiry is released towards the end of this year, Defence is expected to point to Mr Irvine's review as evidence that work is already underway to combat cultural problems inside the special forces.

By tackling any rogue or illegal behaviour domestically, Australia would also be in a stronger position to fend off any external investigation by the International Criminal Court which is currently weighing a decision on whether to launch one against all parties to the war since May 2003.

Former commando Kevin Frost in Afghanistan. ( Supplied, file photo )

A member of the special forces community has told the ABC last year's appointment of Major General Adam Findlay as Special Operations Commander is a "positive sign", because the former SAS soldier has spent time away from the elite unit and he is seen as an "agent for change".

The ABC approached David Irvine to comment on his review, but he declined to do so.

Mr Irvine previously headed the domestic intelligence agency ASIO, and its overseas equivalent ASIS.

Killings under scrutiny

For the past two years New South Wales Supreme Court Justice and Army Reserve Major General Paul Brereton have led the IGADF investigation of conduct by special forces.

Defence has not confirmed whether any particular incident or individual is under inquiry.

In 2016 former Commando Kevin Frost went public about his role in what he described as the unlawful execution of a prisoner of war in Afghanistan.