The Junior Finance Minister Brian Hayes has expressed concern about proposals to increase the Universal Social Charge for top earners.
The suggestion has come from within the Labour Party, and would hit those on more than €100,000 a year, and is aimed at raising €71m for the Exchequer.
Mr Hayes is concerned that raising the USC would represent an income tax hike, something the Government has promised not to do.
The Fine Gael TD said there is room for those on more money to contribute more, but he is not sure this is the way to do it.
Mr Hayes said: "I think the issue is this, we have got to strike the balance between tax hikes and cuts in expenditure. I think there is some room for people at the top to pay a little bit more, whether you would do it that way or not is another question.
"But I think the issue is this, if you keep hiking up income tax willy-nilly across the board, I think it does have a negative impact in terms of jobs."