Anyone who sees any suspicious activity around an ATM should call the police or Crimestoppers (0800-555-111).
An ATM scam targeting bank customers here could be more widespread than first thought, with four machines and up to 500 cardholders already confirmed as targets.
New details emerged yesterday of the lengths the fraudsters are going to to overcome bank security and access thousands of dollars in cash from unsuspecting customers.
Up to 500 card holders are believed to have used four affected ANZ and National Bank machines in Parnell, Ponsonby, Takapuna and Howick, but it still isn't clear how much money has been stolen.
However, one of them, Jacques Ninzigamiye, said the last place he had used his card was in Northcote, on the North Shore, and he had lost $1300, withdrawn at the weekend in Bangkok - a city he has never visited.
The Herald has also learned of another possible case in Orewa, indicating the scam is larger than first thought.
Sergeant Greg Ander, of Takapuna police, said yesterday that it was believed the fraudsters had come from overseas specifically to target the cash machines.
Similar cases over the past six years have involved conmen from Russia, Romania, Canada and Malaysia - with more than $100,000 being stolen in some instances.
"It could be tourists, it could be someone seeking a work permit," Mr Ander said. "There's no reason to suggest they are going to stop. Banks have to be aware of it, and the public need to be vigilant."
He would not discuss the operation to catch the latest fraudsters.
Several people are believed to have carried out the fraud in past couple of months, using "skimming" machines to steal people's information and then sending it to associates overseas.
Police are working with other agencies to try to catch them in the act.
They say that in one instance, in February, more than 200 card numbers were obtained but these were cancelled before any money was stolen.
The fraudsters fit a device over the slot where the card is inserted into the ATM so they can collect information from the card's magnetic strip while a small camera fitted above the keypad records the PIN being entered.
"The best thing people can do is to cover their hand as they are putting the PIN in," Mr Ander said. "If they [the conmen] can't get the PIN, they can't get cash. If the machine doesn't look right, don't use it."
He said it was difficult for people to see the skimming devices when they used an ATM.
ANZ Bank said it appeared that up to 500 cards were used during the days in which its ATMs were targeted.
"We are getting in touch with customers who might be affected and reimbursing them if they've suffered any loss," a spokesman said, adding skimming was a serious problem for all banks, here and overseas.
"We have to be vigilant because fraudsters are constantly coming up with new ways to evade detection. The devices they use are very sophisticated and difficult to detect. We put a lot of work into ensuring customers can have peace of mind when using ATMs.
"All our machines are checked several times a week. We also have sophisticated fraud protection software providing constant, live reports. These flag suspicious transactions or payees with a high degree of accuracy."
He would not discuss why the ATMs in question were not fitted with "green sleeve" devices like other machines.
"All of our ATMs have security features to deter skimming. However, it wouldn't be appropriate to comment on what those features are as this may assist the fraudsters."
Parnell man Matt Gers, 35, received a call from the National Bank late on Saturday night asking if he was in NZ.
"They told me money was being withdrawn from my current account in South Africa and they were alerted to it because there had been four $500 withdrawals in quick succession."
His partner, who had used an ASB card at an ANZ machine, received a similar call from her bank on Sunday morning to say almost $500 had been taken. Another National Bank customer said they had lost $3000 from one account.
In the space of three rapid transactions from a Bangkok cash machine, Jacques Ninzigamiye (pictured) lost more than $1300 in the skimming scam.
The Hillcrest, North Shore, man last used his eftpos card in Whangamata on Thursday and in Northcote two weeks before that.
But on Sunday, he logged onto his National Bank account online and saw he was in overdraft, which puzzled him because he had been paid just two days before.
He phoned the bank and was told money had been withdrawn from an ATM in Bangkok. "I said, 'What? I've never even been there'."
The fraudsters had withdrawn $830, $418 and $88 in quick succession from his cheque account on Saturday night.
The National Bank has put a hold on all of his accounts so the conmen cannot take any more of his money.
Mr Ninzigamiye said that when he reported the theft to the police, they asked if he had given his PIN to anyone.
"One hundred per cent I have never given it out or even written it down."
Mr Ninzigamiye, originally from Burundi, is being supported by his partner until he next gets paid in two weeks' time.
- Amelia Wade