Minister for Foreign Affairs Micheál Martin has welcomed the outcome of the referendum and described the result as good for Ireland.
Mr Martin said there were “many factors” behind the result “ but said it is important to recognise the central role of the generous response of Europe’s leaders to last year’s vote.”
“When the Taoiseach told them that strong legal guarantees were essential, all 26 heads of state and government agreed and this led to a substantial change in public support for ratification which was maintained until the end,” Mr Martin said.
Minister for European Affairs Dick Roche said the focus would now switch to the Poles and Czechs who have yet to ratify the treaty.
"Regarding the Polish and Czech presidents, it is a matter for them and it is a matter for their people. The ball is now firmly in their court," Mr Roche said. "All I can say is that Ireland has lived up to its responsibilities and it is now up to them to live up to theirs."
The swing in support for the treaty is a response to the recession and shows an understanding that Ireland's economic future lies with other European countries, Minister for Finance Brian Lenihan said.
Speaking on RTÉ this morning, Mr Lenihan said the country faced "very serious [economic] challenges".
"The Government is not engaged in any celebratory parties. We are in a very difficult place and that's precisely why people have voted yes."
He said the electorate had recognised "that our markets and our economic future lies with the other European countries. We are in a very difficult economic position and this is an essential first step towards economic recovery."
Labour Party leader Eamon Gilmore described the decision of the electorate as “sensible”.
"I think it was done despite the anger and frustration people feel at a very unpopular government. The biggest obstacle we had throughout this campaign was the unpopularity of the Government."
Former president of the European Parliament Pat Cox said voters had put their country first.
Mr Cox, who headed the Ireland for Europe campaign group, said: “This was a mature vote in which the Irish people rejected those voices telling them to make the referendum a verdict on the government and on national policies.
“The voters also resisted the Trojan horses that were wheeled into this country bearing British eurosceptics, like the United Kingdom Independence Party, the Open Europe think-tank and the British-owned anti-European media.”