The Fianna Fáil TD, Mr Séan Haughey, has told the Taoiseach, Mr Ahern, that he will not be seeking a nomination to run for the party in the European elections in the Dublin constituency next year.
His decision effectively gives a clear run to Dublin TD, Mr Eoin Ryan, who is seeking a nomination.
Mr Haughey wrote earlier this week to the chairman of the Dublin selection committee in Fianna Fáil, Mr Pat Farrell, saying that he had given serious consideration to the option of running for Europe. However, he cited "family considerations" for his decision not to run. Official party sources said he also cited the opinion of his party organisation in Dublin North Central, which had urged him to stay in national politics and continue as a Dáil deputy.
The decision, which has been conveyed to Mr Ahern, comes as a surprise as Mr Haughey had been widely expected to seek a nomination.
He said in an interview on RTÉ Radio earlier this month that Mr Ahern was encouraging him to stand along with Mr Ryan. But with his wife expecting their fourth child in January, Mr Haughey said that working four days a week in Brussels would not be ideal. Mr Haughey felt he had a greater role to play and expressed frustration that he had reached only the "dizzy heights" of vice-chairman of a committee after almost 20 years in the Oireachtas.
Separately, the Labour activist, Mr Nap Keeling, has accused senior party figures of conspiring to exclude him from the ticket in Dublin.
He claimed his interest in a nomination had upset the Labour leadership, which he believes favours the outgoing MEP, Mr Proinsias De Rossa, and Ms Ivana Bacik, Reid Professor of Criminal Law at Trinity College. The intervention of Mr Keeling, a barrister, raises the prospect of another rift within Labour over the selection of candidates for the Dublin constituency.
Labour's campaigns in Dublin in the last two European elections were marked by acrimony over nominations to run for the party.
Mr Keeling said: "I think the Proinsias and Ivana Bacik ticket is basically a set-up job by the powers that be, who think that they represent a good chance of winning two seats in Dublin."
Referring to the pro-choice activism of Prof Bacik, he claimed that "many Labour members have concern's about Ivana's candidacy given her single issue profile".
Prof Bacik rejected this last night. She said: "I know there is negative campaigning going on.
"I wouldn't be involved in negative campaigning. I think my record stands for itself."
A Labour party spokesman said the selection process was being run on a one member one vote basis.
"Each candidate has had the same level of information and resources," he said. "It is up the members to decide who they wish to contest this election."
