A rogue supermarket operator has been told by chain bosses to stop using airport-style handheld scanners to check for light-fingered shoppers.
Countdown has apologised to shoppers of its Countdown Ferrymead store in Christchurch after customers complained of the "heavy-handed" tactics.
Privacy law expert Kathryn Dalziel questioned its legality.
"From a legal point of view, stores have got no right to insist that you stop," she said.
"They've got no right to insist that you submit to that sort of search with a scanner, so I'm just not sure on what basis any shop thinks this is a good idea, either legal or from a PR perspective."
Civil liberties lawyer Michael Bott congratulated Countdown for stamping out the "intrusive" practice.
"People accept it's justified at airports where there is a public safety concern but I fail to see it could be justified when going for your weekly shop," Bott said.
"Unless one is prepared to take one's rights seriously, people almost try to chip away and diminish them."
Concerns were raised by a shopper at Countdown Ferrymead after security staff were seen using handheld body scanners to detect potential shoplifters at the self-service checkouts.
"I was getting prepared to say no they cannot scan me, and under what Act can they do so," said the shopper, who did not wish to be named.
"Maybe they wanted to make people feel uncomfortable or wary but it was all too heavy-handed and invasive for my liking."
After the Herald contacted Countdown head office, the store manager was ordered to stop scanning customers.
And the nationwide supermarket chain has now apologised to patrons.
"We have a numbers of ways to deter theft at our stores, however, it is not our policy to scan customers at checkouts and we don't have equipment in our stores to do this," a Countdown spokeswoman said.
"We have now addressed this with the store. It's now been reiterated with the security team.
"We apologise to customers for any frustration caused to them. It's not the experience we expect in our stores."
The spokeswoman was not aware of other stories using handheld scanners.
She added that theft is a reality of retail, but the company has many ways to deter shoplifters, including the use of CCTV cameras.
The Foodstuffs supermarkets group, which includes Pak'nSave, New World and Four Square, confirmed earlier this year that it uses facial recognition technology in some North Island stores to protect from serial shoplifters.
A sign at the entry to Countdown Ferrymead, which stipulates shoppers entering the store agree to have their bags searched, was also criticised by Michael Bott.
"It is a condition of entry to this store that all bags be presented upon request for inspection at the checkout when leaving the store. Thank you for your cooperation," the message reads.
Bott said he wouldn't even enter a shop with such an imposed condition.
"It's intrusive and unless there's good cause [of suspected theft] then I don't see why they should. What's going to happen next? 'Do you mind if I frisk you?'" he said.