The lack of an Assembly in the North has been “corrosive and damaging”, the Taoiseach has said.
In the US, Leo Varadkar said the deadlock means “there is no effective political engagement on issues of relevance to the lives of the people of Northern Ireland, economically and socially”.
He said a “redoubled effort” is needed after Easter and it may be again up to the Irish and British governments to put forward proposals to break the deadlock.
“I believe the period after Easter should see a redoubled effort on the part of both governments and all of the parties in Northern Ireland to seek agreement on the restoration of the institutions,” said Mr Varadkar.
“It is my view that this will require very close co-operation and leadership from the British and Irish governments. It may be that again the governments will have to table our own proposals to help the parties break the deadlock.”
It comes as Sinn Féin’s Gerry Adams also warned that the institutions in the North “may not be restored in the medium term”.
Both men spoke at an event in Washington last night to mark 20 years since the Good Friday Agreement, where former Northern Ireland special envoy George Mitchell was also a speaker.
Mr Adams said Sinn Féin has made it clear to the Irish and British governments that there can be no going back to direct rule and the best option is for a return of the political institutions.
The North has been without a devolved government for more than a year, with numerous rounds of talks between Sinn Féin and the DUP leading to stalemate and collapse.
Mr Adams said: “It might well be that the power-sharing institutions and all-Ireland political architecture may not be restored in the medium term.
"Until then, and in the interim, the Intergovernmental Conference, which is part of the Good Friday Agreement, needs to be established by the Irish and British governments.”
Mr Adams, who was joined by Sinn Féin president Mary Lou McDonald and deputy leader Michelle O’Neill, said an accommodation had been reached with the DUP last month which was rejected at the last minute.
Speaking earlier in the day at the Brookings Institute in Washington, Mr Varadkar said the lack of a power-sharing government in the North is undermining the operation of other institutions under the Good Friday Agreement.
He described the Good Friday Agreement as a deal which “ended decades of deadly conflict in Northern Ireland, secured a lasting peace for our people, and transformed political relationships that had been stunted for generations”.
He added: “As with any peace, reaching agreement is far from the end of the journey — the path to reconciliation and stable politics can be a long and sometimes bumpy one.
“Continuing differences between the political parties representing the two communities in Northern Ireland mean that there has been no power-sharing executive in Belfast for some time.
“Its absence is corrosive and damaging. It means that there is no effective political engagement on issues of relevance to the lives of the people of Northern Ireland, economically and socially.”
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