It's unclear whether the needles found in Australian strawberries were put in the fruit before or after being imported, Biosecurity Minister Damien O'Connor says.
A punnet of Australian strawberries contaminated with needles was found in St Luke's Countdown supermarket in Auckland yesterday in the first such reported case here.
Woolworths NZ has pulled Choice strawberries from Countdown, FreshChoice and SuperValue. Choice is not one of the brands affected in Australia and it is still on sale there.
Police said a person found the needles before anyone had eaten the fruit.
They are urging anyone who has bought Choice brand strawberries to return them to the store.
Mr O'Connor said the fruit came from Western Australia but was not connected to the brand that was involved in contamination in Australia.
"It's the kind of sordid and sick proposition that does arise when these situations are publicised," he said.
"We hope that it would not be a New Zealander doing a copycat, we hope that it wouldn't happen at all."
He said extra levels of scrutiny of strawberries from Australia should be considered when contamination like this happens.
"It may have been that all the supermarkets should have been checking all the strawberries coming in from Australia into their shops."
This was now a police matter, he said, but measures like supermarket guards would be going too far.
"The actions of one or a couple of irrational individuals can't allow us to be spooked into unreasonable precautions.
"But we do have to check every part of the system."
Countdown, which owns 181 supermarkets across New Zealand, has urged shoppers to cut up any strawberries already purchased. Customers can also return any Choice brand of strawberries for a full refund.
In a statement, MPI said it was working with police and Countdown to investigate the incident.
"MPI supports the action taken by the supermarket in removing the implicated strawberries from their stores.
"Anyone who has purchased this brand of Australian strawberries should, as a precaution, return them to the retailer."
MPI said it was closely monitoring the situation and based on current information, it did not believe further action was required.
The contamination of fruit in Australia has reportedly prompted some growers in New Zealand to consider buying metal detectors. Mr O'Connor said growers in New Zealand should be cautious, and provide the level of scrutiny and safety required.
Supply chain expert Nigel Grigg suspects the needles were put there by a copycat after dozens of cases of similar cases of sabotage have been reported in Australia.
Mr Grigg, professor of quality systems at Massey University, told Morning Report the needles were likely to have been inserted somewhere along the supply chain rather than on the farm where the fruit was grown.
Mr Grigg said it was difficult to protect against this kind of contamination along the entire supply chain, given the volumes coming into New Zealand's ports.
"You can install inspection devices and so on, but the problem is of course these aren't random and naturally-occurring events so a human brain will work around what it knows to be the defences."
Supermarket chain Foodstuffs, which owns Pak'nSave, New World and Four Square, had already stopped stocking Australian strawberries.