The Government is considering a new tax for higher earners to compensate for abolition of the Universal Social Charge.
Reports in The Sunday Times suggest that it may be done through income levies for those earning above a certain amount - or through increases to PSRI.
Fine Gael sources say they want to make sure that higher earners continue to pay more tax after the USC is abolished.
While the threshold for the new charges has not been decided yet, it is believed it will be somewhere above €70,000 but 'considerably less' than €200,000.
It comes after Enda Kenny hinted at "reforming the income-tax system" to cap benefits for highest earners and in order to "keep the income-tax system broad”.
A significant cut to USC rates for 2017 is expected to be a central aspect of Fine Gael's election manifesto.
Both Labour and Fine Gael favour abolishing the charge for low and middle income earners during the life of the next government, but Labour feels it should remain in place for higher earners.
USC was introduced in 2011, replacing the health contribution, and brings in about €4.5bn for the state each year. The latest USC changes will bring marginal tax rate to 49.5% for all earners under €70,044.
USC rates were cut from 1.5% to 1%, from 3.5% to 3%, from 7% to 5.5%. Around 42,500 workers will be removed from paying USC completely due to the measures announced in last month's budget.
Social Democrats TD Roisin Shortall has accused the Government of engaging in auction politics ahead of the election with the proposed tax cuts.
Speaking on the Sunday Show here on Newstalk earlier, Deputy Shortall said "the big danger is that the Government is going to undermine the tax base".
She also stressed it's important to never forget what's happening in the 'real world', with major crises in areas such as housing, the health service and children's services.
Meanwhile tax revenues are reported to show the economy growing at a rate not seen since the Celtic Tiger years.
The returns for November 2015 will be revealed this week, and The Sunday Business Post reports that they are massively ahead of what was predicted.
Corporation tax revenue was €2 billion higher than expected at the end of October this year.
The paper reports that one Government minister has said that Ireland's economic growth could be closer to 10% by the end of the year, rather than the 6.2% predicted at budget time.
