Support for Sinn Féin has climbed by five per cent in the latest Red C opinion poll, published in the Sunday Business Post.

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 boasts 22 per cent support, just three behind Fine Gael at 25 per cent.

Both government parties took a hit of two points, leaving Labour with support at just 8 per cent.

1006 voters were questioned between Monday and Wednesday last week for the poll, which also discussed the same-sex marriage referendum.

It showed 72 per cent in favour and 20 per cent against the proposal.

Michael Brennan, Political Correspondent for the Sunday Business Post, said 8 per cent of voters remain undecided: