Ulster Bank will extend the opening hours of 80 branches in major towns and cities today to assist customers affected by a "major technical issue" that means their balances do not reflect recent payments.
These branches will stay open until 7 pm.
The bank's 60 Saturday-opening branches will open as usual this weekend.
Ulster Bank is now operating on a two-day delay in processing payments. Many transactions due on Wednesday are still being processed.
ATM and online banking services are available but are still reflecting a delay in customers' balances, Ulster Bank said.
On Friday morning the bank updated its advice to customers as follows:
My salary/benefit payment was due into my bank account. What should I do?
If you are trying to access a salary or benefit payment and you cannot access your funds via an ATM, you may wish to visit a branch. To help you with this, 80 of our branches will be open until the extended time of 7pm today and 60 Saturday opening branches will open as usual this weekend. If visiting a branch, please bring your ID and payments details.
Why is my balance on my account not up to date?
The Bank encountered a problem with its technology system in RBS which affected systems in NatWest, RBS and Ulster Bank.
Have the transactions for Wednesday 20 June or Thursday 21 June been processed?
Many credits and debits to your accounts from Wednesday 20 June and Thursday 21 June are still being processed as a result of the technical issue. We are working our way through this backlog of payments as quickly as possible.
Can I see my balance on Anytime, Mobile Banking or on an ATM screen?
The balance on Anytime Internet and Mobile Banking and ATM screen will not be up to date as it may not reflect transactions due to be applied to your account from Wednesday 20 June onwards.
Will I be charged if my account is out of order?
If you've experienced any charges or loss of interest please contact us and we will refund you fully.
Where can I get more information?
We will be posting regular updates to our website throughout today to update you on our progress in resolving this issue.