AIB says it will contact customers affected by a mortgage repayments issue.

It's after issues raised by apparant underpayments to some tracker holders who had transferred from Ulster Bank.

32,000 tracker mortgages were transferred to AIB from Ulster Bank, when the latter left the Irish market.

Some of those holders received letters from AIB recently, which said they had been undercharged in their repayments and that must be rectified.

They faced increases of up to 600 euro from October.

AIB has apologised to customers concerned, adding that it will contact them all in the coming weeks.

Meanwhile, the Central Bank says it has been in contact with both AIB and Ulster bank over the issue.

It adds that it's expected entities rectify any errors or breaches, to ensure customers are treated fairly.