Danske Bank says a glitch with its IBM-managed payments network resulted in customers of its subsidiaries in three countries being unable to use their cards to withdraw money from cash machines.
Customers of Finland's Sampo Bank, Northern Ireland's Northern Bank and National Irish Bank (NIB) in the Republic of Ireland also found they couldn't use some debit and credit cards at the point of sale on Wednesday.
A Danske Bank spokesperson told Finextra that the issue was caused by a problem between IBM and PBS, the national payments network in Denmark. As well as affecting customers in other countries, the glitch prevented some Danske customers from using Maestro international debit cards in Denmark.
Northern Bank's entire ATM network - around 200 machines - collapsed at around 11.00am yesterday. A spokesperson for the bank told Finextra that the glitch in the ATM network was due to a "technical problem with IBM" which supports the network.
The NI bank worked to fix the problem last night and confirmed the system was back up and running at 6.00am today.
Meanwhile, customers of NIB in the Republic of Ireland experienced similar difficulties with their cards, as did Sampo Bank customers in Finland.
According to press reports on Wednesday Sampo customers found that they were unable to use their cards to withdraw cash from ATMs, while payments made with Visa or MasterCard credit cards could not be completed because of a in the verification system.
Ilkka Hallavuo, chief executive of Sampo Bank, told Finnish broadcaster YLE that the bank would compensate customers affected by the glitch.