"It will be used to check photos against our database and help investigate potential fraud," the department said in a statement.
NeoFace is controversial for its other major use globally - identifying up to 1000 "persons of interest" per minute in real-time feeds from CCTV cameras.
In the UK this month, an appeals court ruled the use by police in Wales of NeoFace was unlawful and a violation of human rights.
NEC itself is on the wrong side of a pushback against facial recognition in the US.
There, tech giants Amazon, IBM and Microsoft in June called a halt to supplying the tech to US police in a moratorium over brutality against blacks.
But NEC, like some other major suppliers, has not followed suit.
"We are committed to developing technologies that help support efforts to end racial injustice in our society," NEC said in a statement.
The three that called a halt are relatively small players in facial recognition and a Washington Post tech columnist said the "publicity stunt" would make little difference, especially since the companies would still sell to other users.
'Particularly close' to NZ police
In New Zealand, NEC said it had a "particularly close relationship" with police.
This included supplying finger and palm print biometrics, though facial recognition was not mentioned in NEC's PR material.
It has been reported police here are using US company Dataworks Plus to replace their old facial recognition system.
Police got into trouble in May for trialling facial recognition from highly controversial firm Clearview AI without proper authorisation.
When RNZ asked for more information about NEC or NeoFace, police treated the questions as an Official Information Act request, which takes at least five weeks to answer.
NEC told RNZ none of its facial recognition technology in New Zealand was being used for "any form of surveillance" of individuals.
Its facial recognition algorithms were "embedded " in the Immigration Department, it said in PR material.
It promotes the tech as a way of fostering public safety and security, for instance, for air travellers.
However, the company has been criticised in the UK for being less than transparent about how these all-important algorithms "learn" who to raise the alarm about.
NEC said its products were highly accurate, and it went to "great lengths to ensure our facial recognition algorithms are accurate across racial and other demographic groups".
'Solely' for issuing passports
For the passport processing work here, NEC is partnered with US multinational DXC Technology, which won the contract.
The pair are strongly pushing biometrics online, including promoting how NeoFace can be integrated into lots of surveillance systems at once and use just about any camera technology.
"The opportunity to combine NEC's expertise in biometrics solutions, in particular, facial recognition technology, with DXC Technology's experience in delivering digital transformations through modern, integrated IT systems means our partnership will go from strength to strength," NEC said in its PR material.
It was common for facial recognition tech bought for one reason to "creep" into other areas, Dr Jathan Sadowski of Monash University, Melbourne, said.
"We see a lot of agencies in Australia, the US, the UK, taking something they said was only going to be used for something like passport control... and it's by design to not use them for only one reason," Sadowski said.
Internal Affairs said NeoFace replaced outdated facial recognition technology.
"It relates solely to securely issuing passports rather than their subsequent use."
RNZ asked the department how widely the data NeoFace collects will be shared, how it will be stored and what safeguards around its misuse there are, and awaits a response.
The Privacy Commissioner commonly assesses the impacts of such technology.
Airports are the biggest user of facial recognition technologies globally, and police second.
Sadowski advocates facial recognition's outright ban and calls the suite of surveillance technologies an "urban war machine".
But NEC in PR material defends them, and said many of its "solutions are the best in their class in the world", referring to high scores in independent tests by the US National Institute of Standards and Technology.
In some trials, however, such as by the London Metropolitan police, Neoface returned high fail rates.
The pushback includes some US city councils - San Francisco and Boston among them - banning facial recognition that other councils use en masse to monitor public places.
Boston's ban followed an MIT study that found for darker-skinned women, facial analysis programmes were wrong about a third of the time.
Black Lives Matter campaigners are counting as a win the moratorium called by Microsoft, Amazon and IBM.
Microsoft called a halt "until we have a national law in place, grounded in human rights, that will govern this technology".
Amazon put a one-year moratorium in place on supplying facial recognition to US police.
"It's certainly a win," said Sadowski, but added only a ban would deal with the fact that regulation was too slow to rein technology in.
In the UK court case against South Wales Police, the appeals court this month found the police did an "obviously inadequate" assessment of whether there might be indirect discrimination over sex or race.
'Blazing trails'
NEC has 1000 facial recognition systems in use in 70-plus countries - it was "blazing a trail" with new uses such as for "mega-event surveillance" in Japan, it said.
"We believe that public sector agencies should be able to use advanced facial recognition and other innovative technologies to help correct inherent biases, protect privacy and civil liberties, and fairly and effectively conduct investigations," it said in its statement to RNZ.
NEC declined a taped interview.
It is developing biometric software for frequent flyers with the Star Alliance, which includes Air New Zealand.
NEC counts DXC as one of its top-five partners.
DXC, which was once part of Hewlett Packard, in turn is a close partner of German payroll provider SAP, which has rolled out many government payroll systems in New Zealand.
Industry observers consider SAP is well placed with the government attempting to centralise payroll system processes.
As well as biometrics with NEC, DXC also implements what SAP calls its "Citizen Engagement Accelerator" that is promoted to the public sector and councils.
One key benefit is listed as: "Increase chance of re-election through higher citizen satisfaction levels."
Christchurch city had implemented this technology, DXC said.
DXC did more than $140m of business in New Zealand last year.
Another of NEC's top five partners is California company Juniper Networks that is under pressure over an investigation into an alleged backdoor into its encryption, and the security implications for users.
DXC referred RNZ's questions to the department.
