Nationwide customers are facing difficulties in the run-up to Christmas and are unable to send or receive money.
The banking group said people can use ATMs as normal and there is a delay in transfers but there is no need to resend money.
“Unfortunately, there is currently a delay on outbound payments reaching people’s accounts as well as inbound payments reaching Nationwide current accounts,” said a spokesperson.
“We are working hard to resolve the issue and apologise for any inconvenience caused.
“There is no need for people to resend payments and these will be processed as soon as possible.
“All other services are working normally, and members can continue to use their cards to pay for goods and services, access the Internet Bank and Banking App and withdraw cash from ATMs.”