Fianna Fáil says the European Central Bank needs to take action to ensure that Irish banks pass on interest rate reductions to their customers.
ECB interest rates are at a record low, but Fianna Fáil say customers with mortgages and loans here aren't seeing the benefit.
President of the ECB Mario Draghi is being called on to intervene to ensure that Irish banks pass on the lower interest rate.
Fianna Fáil Finance Spokesperson Michael McGrath, says Irish banks are profiting from charging higher interest rates to variable rate mortgage holders.
Mr McGrath said: "I think it's very clear that the banks in Ireland are taking advantage of the historic low ECB interest rate and the low cost of funds generally that they are facing to maximise their profits, to extract as much money as they can from variable rate customers.
"The banks are accessing at little over 1%, whereas they are charging over 4% to variable rate customers."