Political parties in the North must not walk away “when it comes to the first difficult decision” to be made, the Taoiseach has said about the row in the Northern Ireland Executive over social welfare reforms.

Sinn Féin has opposed social welfare cuts in the North, which the party insists were not agreed to in the Stormont Agreement.

But Enda Kenny told Sinn Féin leader Gerry Adams that when the Stormont Agreement was reached in December, it was accepted and signed off on "and welcomed by the Deputy First Minister, more fulsomely than by Deputy Adams".

Mr Kenny asked: “What has happened that the figures are now different than those he accepted and agreed to before Christmas?”

The social welfare row erupted publicly on Monday when Deputy First Minister Martin McGuinness told the Assembly that his party would oppose the Welfare Bill.

Mr McGuinness and First Minister Peter Robinson each accused the other of reneging on the agreement.

In the Dáil, Mr Adams said it became clear last week that the DUP “was intent on reneging on commitments in that agreement”, and that Mr McGuinness had discovered that it was the DUP’s intention “to provide only partial protection to current recipients of benefits and no protection whatsoever for future recipients”.

Mr Adams claimed this was contrary to the Stormont deal.

When the Taoiseach asked him how Mr McGuinness had found this out, Mr Adams said he “discovered it because we were given papers, we believe, by mistake”.

Mr Adams added: “These are red line issues because the essence of mature politics must be protecting the disadvantaged who need the protection of society.”