New Zealand began operating out of the base before May 2017, which was during the time of the build-up to the final push of the Battle of Mosul, finally recaptured from Isis in July 2017.

A May 2017 briefing to then-Defence Minister Mark Mitchell noted that New Zealand’s involvement at Qayyarah West had not been made public, though it did not say why.

Mitchell did not directly answer questions put to him by Stuff Circuit about Qayyarah West, but said in a statement, “The New Zealand Defence Force was given a strict mandate to train Iraqi soldiers for the fight against ISIL, as well as to train stabilisation forces, and to the best of my knowledge they adhered to that mandate."

“There was no change in that mandate beyond what was announced publicly and all troop training was carried out behind the wire as stipulated.”

Sooden’s research has also revealed New Zealand soldiers are involved in a controversial programme to record the biometric data of Iraqi soldiers. He is concerned about the human rights implications of this, saying the information collected can identify a person’s ethno-sectarian background. “In a sectarian conflict that’s a very dangerous thing.”

He said the New Zealand Government couldn’t guarantee how that information would be used, and “if it gets into the wrong hands - and these are the words of a US biometrics military specialist - it can become a hit list.”

Former Minister Mitchell said “I have no recollection of any briefings on the gathering of biometric information.”

Like Sooden, strategic analyst and former Pentagon official Dr Paul Buchanan is concerned about the collection of biometric data.

“The Iraqi authorities are unreliable when it comes to using it neutrally and professionally, so sharing with them or the Iraqi Security Forces is problematic… The whole issue of data sharing with any Middle Eastern regime is fraught, to say the least.”

Of the aspects of New Zealand’s deployment that had not been made public till now, Buchanan said “to err on the side of prudence is understandable in light of the attacks on allies who publicly disclosed the full extent of their roles in Iraq.”

But he said there were also political reasons for “non-disclosure or misleading official information about the Defence Force mission in Iraq.”

He said emphasising the training aspects of the mission and downplaying the “advise and assist functions that bring the Defence Force into direct combat-related roles” allows the government some measure of insulation from political and public questioning of the mission.

He also believes there’s a “culture of impunity” with regards to foreign military operations.

“They engage in such stonewalling practices because traditionally they have been able to do so and get away with it. Their attitude is ‘why complicate things by involving others and engaging in public debate?’”

The New Zealand mission to Iraq is up for renewal in November this year.

Sooden says before the Government makes a decision, there should be transparency.

“The concern isn’t [just] what they’re doing. The concern is that we’re not being told what they’re doing.”

A spokesperson for Defence Minister Ron Mark said he was unavailable to comment.