Fine Gael has been accused of rank hypocrisy for campaigning against ministers' severance pay while not revealing Enda Kenny's teacher's pension.
Mr Kenny said he would not draw down the retirement package amid claims he was due a 100,000 euro lump sum in April and an annual 30,000 euro payout.
As two new opinion polls put Mr Kenny on course to be the next Taoiseach, Fianna Fail leader Micheal Martin hit out at the party claiming the retirement benefits had been kept hidden from the public.
"The real issue there is hypocrisy," Mr Martin said.
"And I accuse the Fine Gael party of rank hypocrisy in campaigning around the country on this, and doing something else.
"They've talked the talk but they don't walk the walk."
Fine Gael has pledged to scrap severance payments for retiring ministers if elected to power and has urged departing ministers not to avail of the windfall.
The Sunday Business Post reported Mr Kenny would be due a 100,000 euro lump sum for four years teaching in April, and an annual pension of 30,000 euro on top of his politician's salary.
But at a campaign rally at the Aviva Stadium in Dublin, Mr Kenny said he would not be drawing down his teacher's pension.
And he called for Mr Martin to resign his own teaching position immediately.