Separate pre-Budget reports from business group Ibec and the Think-tank for Action on Social Change (TASC) have presented opposing views on the future of income tax in Ireland.
Ibec said Ireland is not a low-tax country and that more than half of taxpayers would benefit from a cut in the marginal rate.
However, in its pre-Budget commentary, independent think-tank TASC said workers in other European countries pay an average of 25% more income tax than Ireland.
Ibec said that while low earners in Ireland pay less tax than the OECD average, middle and higher income earners are paying well above the European Union average.
It wants income tax to be brought below an effective rate of 50%, which is a psychologically important round number.
However, TASC concludes that when tax credits are factored in, no one in Ireland actually pays the higher rate of tax and that the most anyone pays is 30%.
It proposes the creation of a third tax band for those earning more than €100,000 and warns a cut to the higher income tax rate would only benefit one in six.
Budget 2015 will be delivered on 14 October.