Support for Sinn Féin has climbed by 5% in the latest Red C opinion poll, published in the
It more than makes up for the four points the party lost a month ago, after allegations of an IRA cover-up of the abuse of Paudie McGahon.
Sinn Féin now claims 22% support, just three behind Fine Gael at 25%.
Both government parties took a hit of two points, leaving Labour with support at just 8%.
1006 voters were questioned between Monday and Wednesday last week for the poll, which also discussed the same-sex marriage referendum.
It showed 72% in favour and 20% against the proposal.
Michael Brennan, Political Correspondent for the Sunday Business Post, said 8% of voters remain undecided.
"If you ask people if civil partnership is enough - do you need to redefine the institution of marriage - almost 45% would say that civil partnership is fine.
There's definitely evidence that there's soft yes support there. As the campaign goes on, the very high yes vote could certainly drop further."