EU:The Taoiseach, Mr Ahern, led tributes to the president of the European Parliament, Mr Pat Cox, who said yesterday that he would not seek re-election in the poll on June 11th.
With expectation intensifying about Mr Cox's plans when he stands down, Mr Ahern said that the independent MEP had made an "outstanding contribution" during his time as president of the parliament.
While Mr Cox's decision to retire from the parliament was signalled late last week, his official spokesman told The Irish Times a fortnight ago that he was planning to run again for election to the parliament in June.
The decision to leave the race eases pressure on Fianna Fáil to retain its two seats in the South constituency, formerly Munster.
Mr Brian Crowley MEP and Mr Gerard Collins MEP are seeking re-election for Fianna Fáil.
But for as long as Mr Cox was in the race, the reduction of constituency seats to three from four put serious pressure on Mr Collins.
Mr Crowley had the biggest vote in the State in the last election and is seen as the favourite to top the poll in the South constituency in June.
Mr Simon Coveney of Fine Gael is believed likely to secure a seat.
Mr Ahern said it had been a pleasure to work with Mr Cox, at a domestic and European level, particularly during the Irish presidency of the European Union.
Mr Cox had always acted in the best interests of his Munster constituents in his role as a European parliamentarian, Mr Ahern said. "I wish Mr Cox well in whichever path he may choose in the future."
Mr Coveney said he recognised that Mr Cox had made an "immense contribution" during his 15 years in the European Parliament.
"What Pat Cox has achieved while representing Munster and Ireland as an MEP should not be underestimated. He has been a huge success as president of the European Parliament and we in Ireland should be proud of that achievement," he said.
The Labour candidate in the constituency, Senator Brendan Ryan, said he had disagreed with Mr Cox on a range of political issues but had never doubted his ability.
Praising Mr Cox's energy and commitment to the people of Munster, he said his achievements in the parliament showed that it was possible for an effective MEP to make a difference.