Bank of Valletta is in the process of replacing a "good number" of Visa credit cards as a precautionary measure after a possible data leak.

Contacted yesterday, a bank spokesman said the problem revolved around the possibility of card data having been obtained by unauthorised third parties resulting in the "possible fraudulent use of certain cards".

A number of card holders were contacted by the bank's card services unit and informed that their credit card was being cancelled because it could have been compromised and they were being issued with a new one.

The bank spokesman would not divulge how many credit cards - all Visa - had been withdrawn, only saying there was a "good number" of them. He said the bank was in constant contact with Visa, which is understood to have raised the alarm.

The spokesman said this was the first time that credit cards have had to be changed. "Visa and Mastercard regularly inform the bank whenever there is a possibility that some of our cards might be compromised. From our end, we take all the necessary precautions, including the replacement of cards, when necessary," he said.

When asked about clients who were going abroad and needed to use their credit card while overseas, the spokesman said arrangements for immediate card replacements had been made where necessary.

HSBC Malta said it has not been affected by the problem. The bank's head of business transformation, Michel Cordina, told The Times the bank regularly reminds customers to exercise caution and not to divulge any information via e-mail.