An AI expert is warning of privacy creep and a surveillance society.
It comes after Foodstuffs proposed to use facial recognition technology to scan and make a biometric template of each shopper as they enter the premises to see if they match a watchlist of people identified with repeated harmful behaviours.
The privacy commissioner is keeping a close eye on a trial starting at Foodstuffs North Island stores on Thursday.
In Australia, UTS Human Technology Institute fellow Dr Kate Bower, who specialises in AI regulation, has compared using facial recognition technology to taking DNA data.
"Facial recognition is what I'd call a highly invasive privacy technology, and it is a bit different than your standard CCTV camera," she told Checkpoint.
While CCTV only captures video footage, facial recognition on the other hand "actually captures the biometric data of each individual person who walks past the camera".
"It captures a lot of data points from your face and these form of face print and the easiest way to think about this is like it's like a fingerprint or it's like a strand of your DNA."
She explained that facial recognition technology could identify a person in a crowd, and could match them to a database of names.
Bower said it was understandable that supermarkets wanted to reduce theft and dangerous behaviour, but for regular shoppers, she likened it to "being put up in a police lineup every time that you walk into a store". It was like asking for customers' fingerprints every time they entered a store.
"The other thing to consider is that this technology is not perfect. It's quite frequently wrong.
"We know what's happened overseas, where it's in high use, particularly in the United States, but there's been frequent cases of racial bias of people being wrongly identified. We know that the accuracy rates go way down for people who are brown-skinned or black-skinned. That's something that every person should be concerned about."
Māori data ethicist Dr Karaitiana Taiuru has told RNZ there was overseas evidence the technology struggled to accurately identify people of colour, and Māori and Pacific people here would be falsely accused at a higher rate.
"It's not going to be 'if', it will be 'when' the system mistakenly identifies an innocent person and then the human staff don't pick up the differences.
"Then we are going to some very distressing situations."
Bower said it should also raise flags that a private company would be holding biometric information of the public.
"It's really important that we ask questions about where they're storing it, how long they're storing it, can we request deletion of our information, is it being stored in New Zealand or is it being stored in a data centre overseas? Is the police in New Zealand able to access it on request and more importantly, are other law enforcement agencies able to request it from overseas data centres if it's in fact being stored overseas and and what kind of transfers is it the subject to?"
"All of these kind of issues are a bit of a kind of minefield that the supermarkets really don't need to be going into.
"It's really a bit unfair to expect ordinary New Zealand shoppers to be thinking about these serious issues when they just want to go in and buy their weekly shop."
Then there were the issues of children's data being stored, Bower said. "Do you really think it's fair that your six-year-old's biometric information is captured and then matched against the database?".
She said the public should speak up now before the technology starts creeping in public spaces.
"If we allow it to happen in supermarkets ... it will be around us everywhere and then we'll constantly be under a level of surveillance that I think most of us are not willing to accept and particularly for even if we're willing to consent for it for ourselves, are we willing to do so for our children or for our elderly parents who may not be able to fully understand the ramifications of this kind of data collection?"
Foodstuffs consulted with the Privacy Commissioner on the plan, and an independent evaluator has been appointed.
All images of customers will be instantly deleted unless they have committed a crime, or been aggressive, violent or threatening towards workers or customers.
Foodstuffs said the data was not shared by the individual stores with other Foodstuffs supermarkets, or with third parties unless required by law.
Offenders' images will be held for up to two years, and people who help offenders will be held for up to three months.
Images of people under 18 will not be put into the system's record of offenders.