The Irish Fiscal Advisory Council is warning that income tax will have to increase if the pension age is to stay at 66.
It's warning that revenue generated by motor tax and fuel will drop in the coming years, while costs associated with an ageing population - such as pensions and healthcare - are set to increase.
It says if the State is to cover these costs, Ireland will need to move away from being a relatively low-tax country and become more in line with European norms.
But Chair of the IFAC Sebastian Barnes says if taxes need to be raised, they should be targeted at higher income workers.
"We do need to balance it and we need to raise tax in a way that's efficient that doesn't harm growth, but also in a way that's fair and make sure that we're not, in particular as we currently have, taxing people at a fairly high rate on income at a relatively low level of income."
