Bank of Ireland said its fraud prevention team received over 10,000 calls from customers during the peak holiday period from Monday 23 December to Sunday 29 December.
The bank said it received more than 550 calls from customers on Christmas day alone.
The busiest day for calls from customers was 23 December with over 2,800 calls received, with the second busiest being 27 December (1,734 calls) and over 1,100 calls received on St Stephen's Day.
New Year's Day also proved to be busy for the fraud prevention team with just over 1,300 calls.
The Bank of Ireland fraud prevention team is available to customers across Ireland and the UK 24 hours a day, 365 days a year.
Customers call the bank's fraud team for several reasons including spotting a transaction on their account or card that they do not recognise.
They may also call if they are contacted by a fraudster via text, call or social media, or to report a lost card, or if they are worried they may have shared their confidential banking information as a result of one of these contacts.
Research conducted on behalf of the lender shows that three in four consumers want to be able to speak directly with someone at their bank or financial service provider if they fall victim to fraud or are worried about a transaction.
Susan Russell, Chief Executive Officer Retail Ireland, Bank of Ireland said that fraudsters never take a break and are always on.
"As these figures show, customers aren't just concerned about fraud during business hours. They can spot something worrying, or be the victim of an attempted fraud, on any day of the year," she said.
"When that happens, they can call us any time for fraud and security support. I’d like to thank our teams for working to support customers every day of the year, including the recent holiday period," she added.
Bank of Ireland's Emergency Contact Numbers – available 24 hours 7 days a week
Republic of Ireland
Freephone: 1800 946 764 (personal and business)
Great Britain & Northern Ireland
Freephone: 0800 121 7790 (personal and business)
Everywhere outside Republic of Ireland, Great Britain & Northern Ireland
Not Freephone + 353 1 679 8993
Not Freephone + 353 56 775 7007 (Lost/Stolen cards or smart device)
