The Bank of Ireland is raising the Standard Variable Rate on its mortgages by 1.5%, affecting 100,000 customers across the UK.
The SVR will rise from 2.99% to 4.49% in two stages.
There will be a 1% in June this year and a further 0.5% in September.
A homeowner with a £100,000 repayment mortgage will see an £81 increase in monthly payments to £555 a month, according to the financial information firm, Moneyfacts.
The lender said the cost of funding mortgages had increased significantly. It added that its current SVR was considerably lower than the market norm and its rates would remain competitive.
The move comes after the Uk's largest mortgage lender, Halifax, said it would raise its SVR from 3.5% to 3.99% from 1st May.
Standard Variable Rate is a benchmark mortgage rate which large numbers of borrowers revert to after discount offers or fixed rates have expired.