The Fianna Fáil leader says his party will oppose the property tax being put forward by the coalition, because it can't possibly raise €500m.
Micheál Martin also says the elderly must be protected in the budget and has vowed to fight any change to the free travel scheme for pensioners.
It follows comments from Junior Minister Brian Hayes saying that pensioners had escaped the worst of the cuts so far.
Speaking as his Parliamentary Party gathered for a meeting in North Dublin, before the Dáil returns tomorrow, Micheál Martin insisted that only the wealthiest pensioners should be asked to pay up.
"Fairness will demand that those on higher incomes, irrespective of what category of society they belong to or what age demographic they belong to, would pay proportionally a bit more than those who are on the breadline.
"That goes for every sector of society. We do not believe we should target a group of people, such as the elderly or pensioners and say they are rolling in it."