Around 400,000 homeowners are poised to face higher monthly repayments.
Yet another interest rate hike is expected when the governing council of the European Central Bank meets today.
An increase of 0.75% is on the cards as the bank attempts to control inflation in the eurozone.
It'll be the third interest rate hike this year which between them will amount to a 2% rise.
Economist and MD of Financial Services at Sherry Fitzgerald, Shane Quinlan, says it will really hit homeowners in the pocket:
"If you look at a typical tracker maybe with about 200,000 remaining over a 15 year term, that means an extra €180 per month, which I suppose equates to about 2000 per year. There is speculation we see another increase for the end of the year and we could be possibly at 3% around the middle of next year. That would mean an extra €300 per month for a typical tracker customer, you know, 3,500 per year so the change is significant."
