AIB is to increase its interest rates on new fixed rate mortgages by 0.5% from the close of business on Friday.
It is the first of the three main banks to raise mortgage rates in the wake of rises announced by the European Central Bank (ECB) in September.
The increase will apply to new fixed rate mortgages, with existing fixed rate and variable rate mortgages unaffected.
A new mortgage is one that is either new to AIB or is being switched to AIB, the bank said.
Customers who draw down a new mortgage by November 14th can avail of the previous rates.
The new rates will be applied to existing customers who are entering a new fixed rate period after October 14th.
The change will take affect across the AIB Group which includes AIB, EBS and Haven.
In a statement, the bank said: "These changes will not affect any of the bank's variable or tracker mortgage rates, while existing fixed mortgage rates are also not affected."
AIB said a monthly repayment on a new €100,000 five-year green fixed rate mortgage, with a loan to value of 50% to 80% over a 25-year term, will be €455.91.
The previous monthly repayment would have been €431.01, it added.