Allied Irish Banks
The government has said it will consider legislation to force banks to pass on ECB cuts if they do not do so voluntarily.
Local lenders have been increasing rates on standard variable mortgages amid losses from fixed-rate mortgages and those tied to the ECB rate.
AIB, which was effectively nationalised last year after losing billions of euros in a property crash, said in a statement that it had decided not to pass on the cut as it had not passed on two 25-basis-point hikes in the ECB rate earlier this year.
It said it offers the lowest priced variable mortgage rate on the Irish market.
(Reporting by Conor Humphries; Editing by Elaine Hardcastle)