Bank of Ireland says it is aware of reports from customers about problems with payments they were due to receive into accounts this morning.
It is understood that tens of thousands of public servants have not been paid. The Department of Public Expenditure and Reform said it is looking into the problem.
Gardaí, nurses, teachers and workers at An Post are among those whose salaries have not arrived in their bank accounts.
Workers at a number of private companies are also reporting that they have not been paid.
A spokesperson says the bank is investigating the situation.
However, the bank said that it is not aware of any problem with their systems at the moment.
AIB says there are difficulties with payments coming out of Bank of Ireland accounts, and is telling customers to keep watching their accounts throughout the day.