Taoiseach Bertie Ahern is today working on a damage-limitation exercise after Ireland rejected the Nice Treaty.
However a re-negotiation looks unlikely after substantive changes to the Treaty were ruled out by European Commission President Mr Romano Prodi.
Speaking on RTÉ radio, the Government's chief negotiator on the Nice Treaty, Mr Noel Dorr, added there would be a great unwillingness on behalf of Ireland's EU partners to re-open negotiations on the Treaty.
Mr Dorr added politicians must try to understand the message from the electorate.
Mr Ahern will speak personally to a number of European Union leaders about the consequences of the Irish electorate's refusal to back the plan for the Union's future.
A bitterly disappointed and embarrassed Mr Ahern, together with Minister for Foreign Affairs Mr Brian Cowen will follow up the telephone contacts with face-to-face meetings with their counterparts in Europe next week.
Mr Ahern highlighted all the potential consequences of the surprise plebiscite decision - but also stressed that he fully accepted the outcome.
The Taoiseach commented minutes after official figures confirmed that the Treaty of Nice had failed to secure approval by 54 per cent to 46 per centin the nationwide poll.
Soon afterwards European Commission President Mr Romano Prodi issued a statement, expressing his disappointment. But he, too, said the democratic process had to be respected.
Mr Prodi stressed that the Commission and the current Swedish presidency of the EU would do all they could to help the Irish government "find a way forward."
And he added on behalf of the commission and the presidency: "We trust the Irish government will make every effort to secure ratification of the Treaty of Nice within the agreed timeframe."
That was seen as a clear message that the treaty could not be changed, but that every effort would be made to meet the concerns raised during the referendum campaign.
One result of the European stance could lead to a second Irish plebiscite on the issue before the end of the year to permit the present timetable for advancing EU admission of 12 central and eastern European states to be met.
Ahead of that, though, Mr Ahern is set for bitter political criticism at home for his handling of the referendum.
Treaty opponents, basing their resistance on a perceived threat to Ireland's neutrality, said the poll should not have gone ahead without a fuller debate of all the issues, and there have also been claims that some ministers acted only half-heartedly in their bid to secure electoral backing for Nice.
Irish Labour Party leader Ruairí Quinn said he would raise the issue in the Dáil, and insisted that the blame for what had happened lay with Mr Ahern and his Government.
Mr Ahern admitted that the Yes side had not succeeded in "overcoming the negative fears and perceptions, which in many cases were generated around issues largely outside of the treaty."
He also said: "While I am certain that the vast majority of the Irish people remain strongly committed to the European Union and enlargement, it is clear that there are genuine anxieties and concerns about the future, which go well beyond the terms of the treaty itself.
"We are going to have to reflect deeply on how those may best be addressed."
Opponents of the Nice concept included Sinn Féin and their leader Mr Gerry Adams said: "People have indicated that they care about the future of this island and the future relationship with the European Union.
"The government tried to rush through the referendum without a debate. They tried to do it quietly." PA