The State is beginning an "extended period of reflection" on the future of Europe, the Taoiseachsaid at the EU summit in Gothenburg in Sweden today.
Mr Ahern told fellow EU leaders it was too soon to work out how to reverse the referendum result rejecting the Nice Treaty or to talk about how to resolve a difficult situation.
Mr Ahern said: "We genuinely need, at national level, an extended period of reflection.
"I have announced a national forum on Europe. I hope this will allow for more systematic and extensive debate on the EU and its future direction."
Mr Ahern said the No vote should not be seen as a vote against enlargement.
"Most of the leading No campaigners were at pains to say that they supported enlargements and this has since been repeated by them," the Taoiseach said.
But he identified a sense of detachment from the workings of the EU as a concern for Irish citizens. "The result of our referendum graphically underscores what I believe all of us around this table already know: that there is, unfortunately, a widespread sense of disconnection between the institutions of the Union and its citizens," he said.
The result reflected frustration at a lack of clarity, openness and responsiveness in how the Union conducts business, Mr Ahern added.
"There is a real and urgent need to focus on how we can make the union more meaningful to our citizens and on how its democratic accountability can be strengthened," he said.
Though there was sympathy for Mr Ahern's difficulties, the member states sent a clear message that enlargement would take place, despite the Republic's rejection of the treaty.
Mr Ahern thanked EU leaders for their understanding. He said the Government was determined to work with them to find a acceptable solution which would lead to a successful enlargement of the Union.
The Minister for Foreign Affairs Mr Cowen said the Government now wanted a calm, rational discussion over the treaty and other issues so the Government could come forward with another proposal to be put to a referendum in 2002.
He said the 15 member-states and the 12 candidate countries believed the treaty was the sole gateway for enlargement to proceed.
"The people in Ireland will need a period of reflection to take on board that legal and political reality being re-iterated here this week," he said.
At today's meeting British Prime Minister Mr Tony Blair's spokesman said: "The Prime Minister is a keen champion of enlargement. It is important for European prosperity, job and trade."
But he added: "A protocol clearly stating that Irish neutrality is not affected by the Treaty's provisions on setting up a new defence capability to complement NATO might be a solution."
Additional reporting AFP