The thieves are sending text messages to consumers to alert them to security “problems” with their debit and credit card accounts.
The texts, purporting to come from big banks, also contain a phone number for a hotline, which consumers are urged to ring.
“When you call the number you get an automatic message welcoming you to the bank mentioned in your text,” said British consumers’ association Which.
“You’re then asked to enter your card number and personal details [like your PIN].”
Armed with basic information like a credit card number and PIN, crooks can make bogus bank cards and take money out of cash machines.
The thieves use bogus cards in places like the US where security measures like chip-and-pin on bank cards have yet to be introduced fully.
In the text messages, consumers are often told to ring a local or national Irish telephone number but the calls are re-routed abroad via the internet to the fraudsters.
Yesterday, Ireland’s banks warned customers against responding to such texts, saying they would never ask for such information.
Consumer watchdogs said the scam — known as “vishing” — was another version of fraudulent emails asking bank customers to log on to fake websites and divulge their account details.
The Irish Payment Services Organisation (IPSO), which represents the banks, said customers must be vigilant when giving account information on the phone.
“If they ring their banks they must be sure they are ringing the same telephone number as the one on the front of their statements or an official one in the phone book,” said spokeswoman Úna Dillon.
The fraudsters set up the scam so they can tell which bank a consumer is with the minute they call the telephone number contained in the text.
Yesterday, the Irish Banking Federation said Ireland’s banks would never require a customer to ring up and divulge the PIN number they use in cash machines.
“Even the banks never see your PIN — and they do not ask for it,” said federation spokesman Felix O’Regan.