Bank of Ireland is refunding €3m to ATM users who left the money from cash withdrawals in the ATM machines they were using.

When users complete a transaction and walk away from a Bank of Ireland ATM machine, leaving their cash and/or card behind, the machine pulls the money (and card, if it is left) back in after a certain period of time.

However, during a four-year period ending in October 2009, those users' accounts were still debited for the cash by Bank of Ireland.

Bank of Ireland said that this issue arose following the installation of anti-fraud measures, which resulted in the normal system response of an automatic refund failing for these particular transactions.

The bank discovered the issue during internal monitoring.

Bank of Ireland is refunding €1.3m to 14,000 of its own customers this week.

A further €1.7m in refunds to 29,000 customers of other banks who left their cash in Bank of Ireland ATM machines will be paid to those banks and distributed to their customers as soon as possible.

Bank of Ireland has apologised for this error and reassures all cardholders who use Bank of Ireland ATMs that since October 2009 it has enhanced procedures for handling all such incomplete transactions so that customers accounts will be immediately refunded.

Bank of Ireland said that about six people per ATM machine per year walk away leaving their cash and/or card.

Bank of Ireland dispenses about €16.6 billion through its ATM network every year.