Stuff Circuit's The Valley not only inspired the NZ Defence Force to launch a legal investigation to the allegations raised, it is also up for a number for a number of prizes at this year's NZ TV Awards.

Outgoing Defence Force Chief Tim Keating has revealed there is an investigation under way into allegations made in The Valley documentary.

The Stuff Circuit series looked into the 2004 SAS raid in Afghanistan which led to the awarding of a Victoria Cross to Willie Apiata.

In 2017, Keating said he would respond publicly, but he failed to do so.

On Thursday morning, when asked by Stuff Circuit why he hadn't, he said because of the seriousness of the claims, there was a legal investigation under way and he would not give a timeframe.

READ MORE:

* The Valley: NZ's legacy in Afghanistan

* NZDF responds to Afghanistan investigation

* NZDF disputes bodies of dead Afghan soldiers were mistreated

* Meet the investigators behind The Valley

* Criticism of SAS actions before and after Willie Apiata's VC firefight

MAARTEN HOLL/STUFF Outgoing Defence Force Chief Tim Keating. (File photo)

"All those allegations that were made in the documentary series are being looked at by us to see if they reach a threshold," Keating said.

"Every allegation is a legal process to a point of whether they are well-founded or not well-founded.

"So I'm looking at all those allegations, I'm compiling all the information that was provided in the accusations that were made, and our knowledge.

"And at a point, which will be soon, I'll release my findings of whether this is well-founded or not well-founded."

Keating said the investigation was following a legal process under the Armed Forces Discipline Act and the Defence Act.

"It's not only accountable to me, it's accountable to the Attorney-General and the Solicitor-General. I will conduct a process the same as any other allegations that are made under criminal law."

When asked how long it will take, he said: "You don't respond immediately, you take due process. And we should be held accountable for any allegations, but we should be held account to a lawful process."

While he was due to stand down at the end of the month, he said the process would continue. "It's not about me, the warrant of the office is continuous. I'd like to get it done before I'm gone, but I'm not going to rush the process."

It's the first time the Defence Force has revealed the investigation.

Green Party defence spokesperson Golriz Ghahraman said the investigation highlighted the importance of robust investigative journalism.

"Holding NZDF, including the SAS, accountable for misconduct ... is essential. In fact it is required by NZ and international law.

"Both the investigation itself and any follow up sanctions we hand down to perpetrators will restore faith in the integrity of our defence forces, which for the most part are incredible men and women committed to upholding our common values in their work," she said.

In the documentary, villagers and military sources said NZ SAS troopers had provoked the firefight, mistreated bodies of the dead, kicked in doors and tied up innocent civilians.

The Defence Force detailed a 34-page response to the allegations raised in The Valley, and admitted that Afghan authorities spoken to as part of the documentary may be right.

The documentary series included journalists from the Stuff Circuit team going to the site of the Battle of Baghak, where two soldiers from New Zealand's Provincial Reconstruction Team (PRT) died in an August 2012 firefight with insurgents.

Four Afghan soldiers were also killed.

In its response in 2017, the Defence Force conceded its inquiry into the deadly battle may have got things wrong.

And it confirmed that friendly New Zealand and Afghan forces may have fired at each other.

The Afghan soldiers spoken to by Stuff Circuit for The Valley were never interviewed by the New Zealand military Court of Inquiry which looked into the battle at the time.

The inquiry concluded that while two of the wounded soldiers were likely hit by friendly fire, the remainder of the casualties were from insurgents.

The Valley also revealed that PRT soldiers were involved in a programme to collect biometric data for international allies and reported on overseas media claims that data from the programme had been passed to the CIA.

Since taking up the defence post in 2014, Keating has repeatedly refused to be interviewed by Stuff Circuit.

With his departure looming at the end of the month, Stuff Circuit decided to approach him as he left a select committee at Parliament, flanked by senior staff.

When asked why he had never agreed to an interview for the documentary or previously, he said he objected to "trial by media".

He will be replaced on July 1 by Air Vice-Marshal Kevin Short.

Former Prime Minister Helen Clark, who announced Apiata's VC, called on military leaders to front up over the allegations when they aired in 2017.

Apiata was recognised for bravery after carrying a seriously wounded soldier 70 metres across a battlefield through enemy fire.

Clark described his actions as act of heroism.

But she had "no recollection whatsoever of hearing of the events alleged to have occurred before and after the firefight involving Willie Apiata and his colleagues".

"I do think, however, that the New Zealand Defence Force should respond to the allegations made by villagers about the treatment they received before and after the firefight occurred," she told Stuff Circuit in 2017.

"The behaviour described would not in my opinion meet the standard expected of New Zealand Defence Force personnel."