The European constitution offers the best way forward for the EU and should be kept "intact", according to Minister for Foreign Affairs Dermot Ahern.
Offering the Government's strongest opposition to renegotiation of the treaty, Mr Ahern said it had been defeated in France and the Netherlands but passed in a dozen countries.
"It is unfortunate that the results in France and The Netherlands have cast a shadow across the ratification process," he told the National Forum on Europe in Dublin Castle.
"Nonetheless, we continue to believe that the constitution offers the best available way forward for the EU."
He said: "There are those who wonder if the constitution needs to be reopened in response to the referendum results. It is unlikely that a renewed round of negotiations would lead to a significantly different outcome.
"There are no readily-identifiable textual or substantive changes that would guarantee its acceptability to electorates across Europe. The text as it stands reflects a delicate balance of interests.
"It cannot easily be transformed into an a la carte menu from which member states can choose their favourite provisions. In all likelihood, we would each prioritise different elements of the package.
"The best option, therefore, is to keep the constitution intact, and to review its prospects once the current period of reflection has come to a close."
The Government, he said, would not set a date for a referendum on the constitution "until the picture becomes clearer at European level", though it would "make an active contribution" to the debate there.
The negotiation of the constitution had been a "significant achievement" that straightforwardly expressed the EU's values and objections, and helped to bring the EU's institutions up to date.
"The constitution simplifies the existing treaties. It fuses provisions from a range of treaties elaborated over the decades into a single document that is easier for the public to grasp.
"Most of all, it offers a blueprint for a more effective and cohesive Union, one fit to meet the challenges of the future," Mr Ahern told the forum, which is chaired by Senator Maurice Hayes.
He acknowledged that the last year had produced "real setbacks" for the Union, with "an indifferent public attitude" to a constitution that had been "crafted with such care".
However, the French and Dutch referendum defeats could not "reasonably be viewed as a rejection of the European Union", though they did offer "a wake-up" call for the EU's supporters.
Disagreeing with the Minister's analysis, Labour Dublin MEP Proinsias De Rossa said it was "almost inevitable" that the constitution would have to be changed if it was to get the necessary EU support.
Sinn Féin's delegate to the forum, councillor Daithí Doolin, said "the EU's political elite" had to recognise the reality that the EU was "in crisis".
"The elite had scrambled to blame the French workers. But the people spoke, and rejected the constitution in two countries. These people are politically-literate and well read."
Green Party councillor Deirdre de Burca said Mr Ahern had "very clearly" set out the Government's support for the constitution "even though resistance" to it had grown since the French and Dutch defeats.
Socialist Party TD Joe Higgins said the Minister found it "disquieting" that the French and Dutch had rejected the constitution. "I find that a very arrogant analysis."
He said ordinary EU workers were increasingly concerned about globalisation, the exploitation of migrant workers and the threat such workers posed to existing wage levels.
Civil and Public Servants Union (CPSU) leader Blair Horan said leading figures in the Union, such as European Commissioner Charlie McCreevy, were increasingly opposed to European social standards.
Mr McCreevy landed himself into a major row in Brussels after he appeared to suggest that Swedish national pay deals interfered with workers' freedom of movement.
