People have been warned not to give out personal financial information over the phone after a number of people were scammed out of thousands of euro in phone calls from people claiming to be security managers at a well-known retail store.

The vishing scam involves fraudsters calling a person on their landline and claiming that there has been an attempt to fraudulently use their credit or debit card in the shop.

They then attempt to extract personal financial information.

If that request is denied, the person is advised to contact their bank using the phone number on the back of their card or gardaí, with a local garda phone number being provided by the caller.

The scam occurs when the person being called hangs up their landline and redials without listening for a dial tone.

Detective Superintendent Gerard Walsh said some landlines remain open for up to 60 seconds after the person hangs up and when they phone their bank or the garda phone number they have been given, they end up speaking to the scammers because the original call has remained active.

"They pick it up and say 'Hello this is your banker or 'Hello this is the garda station' and they go ahead and they give them the information they wouldn't give to the security managers," he said.

Det Supt Walsh urged people to listen for a dial tone before making another call and to treat any unsolicited calls with scepticism.

He said the scam has worked on a number of occasions, with one individual losing €38,000.