At least two dozen customers have had their bankcards compromised due to a skimming gang operating in the Tauranga and other cities, one local banking official said.
Police said last weekend that three people lost a total of more than $1000 after their bankcards were cloned, and used in the Brookfield area.
Detective Sergeant Ryan Yardley said Tauranga police had received several reports over the past week from people who had been victims of bankcard skimmers.
"We are currently investigating these reports and ask anyone who believes they may have been targeted to report the matter to police immediately and notify their bank."
Mr Yardley said the banks involved were currently making contact with their customers, and due to the ongoing investigation the exact number of victims was not available.
Kiwibank's communications manager, Bruce Thompson, said Kiwibank ATMs had been targeted along with other banks' machines in a number of different towns, including Tauranga. Mr Thompson would not reveal the exact locations of the ATMs to ensure the police investigation was "not compromised".
But he had been made aware that at least two dozen customers from a number of different banks both locally and in other cities had their cards compromised.
"As soon as Kiwibank identified a skimming device had been placed on our machines we contacted the affected people and immediately reversed any fraudulent transactions."
Mr Thompson said affected customers would be reimbursed and new bankcards issued.
These skimming devices are sometimes left on the ATMs for only two to three hours and then removed and placed onto another machine somewhere else, he said.
"We urge people to look closely at the ATM machine before using it and always cover their PIN with their hand when making a withdrawal."
A BNZ spokeswoman said no BNZ machines had been skimmed but a BNZ customer had their bankcard compromised at a Kiwibank machine.
ANZ senior external communications manager Stefan Herrick said there was no indication there had been fraudulent skimming activity on any of the bank's ATMs.
"But a number of ATM cardholders had their cards compromised by using another bank's affected ATMs and these customers will be reimbursed for any loss and issued new cards."
ANZ would continue to monitor ATM transactions for anything out of the ordinary, he said.
Bay of Plenty Times sports writer Peter White was among the victims.
Mr White, who is a TSB customer, said he received a call from the bank on Tuesday.
"They told me they had cancelled my eftpos card because it was used a couple of weeks ago at ATM at Paper Plus in Grey St, which is one of the targeted machines.
"Fortunately my bank account had not been touched but I am impressed TSB took the initiative without asking first to cancel my card in case I was hacked," he said. "It's inconvenient having to wait for another eftpos card to arrive, but I'm grateful to TSB as the skimmers did not get the chance to clean out my account."