The Fine Gael leader, Mr Enda Kenny, led tributes to the Taoiseach and the Government in relation to Ireland's presidency of the European Union and its successful conclusion of negotiations on a new European constitution.
Speaking at the forum on Europe, Mr Kenny said the treaty, agreed in Brussels last month, deserved to be called "the Treaty of Dublin".
"It's not usual for politicians to give public credit but I want to give mine, and I want to warmly congratulate the Taoiseach and the Government on a very successful conclusion to the Irish presidency of the Council of the European Unions," he said.
"We may well differ on a range of other issues, and policy matters, but in respect of your conduct and your ministers and your Government, it has been exemplary and first class."
Singling out the work of the Minister of State for European Affairs, Mr Dick Roche, and the Minister for Foreign Affairs, Mr Cowen, Mr Kenny also paid tribute to the "sterling work" of the numerous Irish civil servants involved in the presidency.
Mr Proinsias De Rossa, Labour party president and MEP for Dublin, also congratulated the Taoiseach and his ministers, describing it as "a major achievement."
However, he criticised as "inadequate" the process through which Mr Jose Barroso was nominated to be president of the European Commission.
"What seems to have been completely forgotten in this process is the requirement under existing treaties for the European Parliament to be consulted by the presidency on the acceptability of the proposed nomination," he said.
Speaking on behalf of the SDLP, Mr Alban Maginness MLA said it was "a matter of great pride to see how successful the Irish presidency was".
"It emphasises the value of the EU for Ireland and small countries," Mr Maginness said.
Meanwhile, the Taoiseach, and Senator Maurice Hayes, chairman of the Forum on Europe, led tributes to the secretary-general of the forum, Mr Wally Kirwan, who is retiring this week.
More than 20 speakers paid tribute to Mr Kirwan, who joined the Civil Service 43 years ago.