Fianna Fáil leader Micheál Martin has accused the Government of neglecting the issue of Northern Ireland by dramatically reducing its engagement.
In his annual Bodenstown address he also questioned the workings of the Good Friday Agreement.
Mr Martin told supporters that the reality was that in many areas like child poverty, things were getting worse in Northern Ireland and people were entitled to question whether the political process was working.
He claimed that in the Assembly and the Executive, Sinn Féin and the DUP were putting party political advantage ahead of the common good.
Mr Martin cited a claim from Peter Robinson in a largely unreported speech this week where the First Minister claimed Sinn Féin were for devolution but against the difficult decisions that go with it.
He also said the Government had had the bare minimum of meetings concerning Northern Ireland, accusing it of backing away from the agenda of developing the cross border institutions.
Sinn Féin leader Gerry Adams described Mr Martin's comments as "bogus".
He said the end of the conflict, the peace process and the power sharing institutions are among the greatest achievements of modern years.
"Sinn Féin on the Executive is attempting, in the absence of fiscal powers, to manage a serious economic crisis and is succeeding much more effectively than Fianna Fáil in government or in opposition has.
"Micheál Martin's comments have more to do with his fear of Sinn Féin in the south than a concern about the north", he said.