The Nice treaty represented a proud achievement for the State, the Minister for Foreign Affairs told the Oireachtas Joint Committee on European Affairs yesterday.
Mr Cowen said the Government would decide whether to hold a referendum once the Attorney General had examined the full legal text of the treaty.
"If the assessment is that a referendum is required we will confidently take on the task . . . of explaining to the Irish people why the treaty, which paves the way for enlargement, is in the best interests of both Ireland an the European Union," he said.
"I firmly believe that the agreement at Nice was an achievement of which all of us as Europeans can be proud, and one that reflects well on the European Union and its leaders' ability to take the tough decision necessary in the common interest," he added.
Mr Jim O'Keeffe TD, Fine Gael, said public debate on the agreement was needed.
"A lot of ground has to be made up to explain to the public the complexity of the issues involved," he said.
Mr Ulick Burke TD, Fine Gael, said the treaty was "a success for Europe but a failure for Ireland" because of the loss of the automatic right to a commissioner and the reduction in voting power on the Council of Ministers and in the European Parliament. Mr Niall Andrews MEP, Fianna Fail, said relinquishing a commissioner was "a very generous gesture" by the Government in the interests of enlargement.
Responding, Mr Cowen said the loss of an Irish commissioner was "a fair outcome" as it would come into force only when enlargement was concluded, possibly a decade away, and it would then be subject to a vote requiring unanimity.
Mr Cowen also described the retention of 12 MEPs as "a successful outcome", as proposals tabled at the summit suggested nine seats for the Republic. Mr Sean Barrett TD, Fine Gael, said he was deeply disappointed by the outcome as it had resulted in a major shift in power to the larger states.
Senator Avril Doyle, Fine Gael, said enlargement should proceed at a pace that ensured social and economic stability. Ms Patricia McKenna MEP, Green Party, urged the Government not to hold any referendum on the treaty simultaneously with another issue such as abortion.