AIB has released a statement after some mortgage holders did not receive interest relief payments for February.
The bank says the outstanding relief payments will be paid in full, in one payment, as soon as possible.
Around 1,600 accounts were affected.
AIB said the relief payments were not made at source as the last day of February fell on a weekend.
The statement also says that AIB regrets any inconvenience caused, and that the Central Bank of Ireland is being kept fully informed on the matter.