They are working to resolve the issue.
Some Ulster Bank customers are experiencing delays in credit payments on Friday afternoon.
10,000 social welfare payments were not processed this morning due to technical issues with the bank.
A statement issued from Ulster Bank earlier on Friday apologised for the delay and said that they were working to fix the issue "urgently."
"We're experiencing delays applying credits to some customers' accounts, which we’re working to fix urgently," they said on Twitter.
"Sorry if this is causing you problems. We'll post an update once we have more information. If you need help send us a private message or message us securely in our app."
The Department of Social Protection confirmed that 10,000 social welfare recipients have been affected by the issue.
"Ulster Bank has informed the Department that 10,000 social welfare payments have not been made to customers this morning, Friday 25 October," they said.
"Ulster Bank is working to resolve this issue so that these payments can be made by close of business today."
The bank later added that they are "continuing to investigate why these credits have not been applied to customers’ accounts and we will provide an ETA as soon as possible for these to be applied."
It is not known exactly how many accounts have been affected by the issue.
Ulster Bank has told the Department that it will provide affected customers with cash through their branch network.
