Labour Party leader Pat Rabbitte has claimed the Government is in part to blame for the current impasse in the Northern peace process.
In his opening address to his party's annual conference in Tralee last night, Mr Rabbitte also accused the Government coalition parties of playing "political and ideological games" in relation to aviation policy and said they had not acted in the national interest in agreeing to sell a majority stake in Aer Lingus.
He said the current situation in Northern Ireland represented "yet more Government failure".
"The tacit and unspoken decision of both Governments to pander to the extremes of politics has led inevitably to a situation that is more divided than in any recent period."
He believed "strongly that the two Governments must learn the lesson that peace and progress must be built on an inclusive basis".
While the DUP was the primary cause of the current impasse, according to Mr Rabbitte, the "cynical manoeuvring of Sinn Féin has driven deep wedges into the peace process".
"The cynicism of their approach to the peace process is matched only by the continuing duplicity of the IRA itself, which promises to consider disarmament and disbandment, but which secretly continues to recruit."
In relation to the recent decision on the building of a second terminal and the partial sell-off of Aer Lingus, Mr Rabbitte said although there had been speculation on which party in Government won or lost, the only losers were the travelling public.
"Because of the incredibly stupid row that has taken place between half-baked ideologies, there will be no additional capacity for years to come [ at the airport]."
He also said the "willingness of the parties in Government to play political and ideological games" is a "scandal". "It is our airline, not some plaything to be tossed around at the whim of a political party."
He said Labour had no objection to Aer Lingus being in a position to seek private investment, but that the sale of a majority stake was not in the national interest, as there could be no guarantee that Aer Lingus would not become a feeder airline for some European hub.
"I know it's not fashionable to say so but the sell-out of Aer Lingus is a shameful decision, that no amount of spin or bluster can cover up."
Mr Rabbitte also called on party delegates to support a motion calling for a Yes vote in the proposed referendum on the EU constitution, once an acceptable wording has been published by Government.
"I see the [ EU] constitution as representing a useful set of institutional reforms designed to help an enlarged Europe function more efficiently on behalf of Europe."
Labour had already made it clear to Government during discussions on the proposed wording that a formula that would allow for substantial changes to the Constitution in the future without a referendum was unacceptable to the party.
The so-called "triple lock" mechanism could not be undermined by the wording either, he said. The mechanism requires a UN resolution, Government decision and Dáil consent before Ireland takes part in military action.