Fianna Fáil TD Éamon Ó Cuív has called for Micheál Martin to be replaced as leader and is seeking a "new direction" for the party.
Mr Ó Cuív, a grandson of the party's founder Eamon De Valera and a long-time opponent of the direction Mr Martin has taken Fianna Fáil as leader, made the comments on Today with Clare Byrne on RTÉ radio this morning.
He criticised the party’s performance in the general election and said that a recent opinion meant that the party was in an “existential crisis”.
A Business Post/Red C poll at the weekend put support for Fianna Fáil at just 10 per cent, the latest in a series of polls which have shown party support plummeting since the general election. The poll showed Fianna Fáil's coalition partner Fine Gael at 35 per cent and Sinn Féin on 27 per cent.
Mr Ó Cuív, a former mininster and deputy leader of the party, said it should look at the poll results and decide it needed a change of direction.
Prior to the formation of the Government, he opposed Fianna Fáil’s deal with Fine Gael and the Green Party and said it should talk to Sinn Féin about a coalition.
Mr Ó Cuív has previously warned that if Fianna Fáil continued on its present course, there would be two big parties in Ireland, but Fianna Fáil would not be among them. Instead, he said, Sinn Féin and Fine Gael would dominate the next election.
His intervention comes amid growing unrest among some Fianna Fáil TDs about Mr Martin’s leadership.
Last week, Fianna Fáil backbench TD Marc MacSharry was critical of Mr Martin's performance at a meeting of the parliamentary party, while other TDs have complained that Mr Martin has excluded them from an input into policymaking and Government decisions.
Two successive Ministers for Agriculture have also departed – Fianna Fáil deputy leader Dara Calleary resigned after the Oireachtas golf dinner, while Barry Cowen was sacked after revelations about a drink driving incident four years ago.
Mr Martin also had to deal with a wave of unrest among his backbenchers when they were omitted from his ministerial and junior ministerial nominees on the formation of the Government, with several criticising him publicly - some in extremely harsh tones - on local media.
Party sources say that there is significant unrest in the parliamentary party with many members privately - and some publicly - critical of Mr Martin’s leadership.
While the Cork TD has often had an uneasy relationship with elements of his parliamentary party since he became leader - his position in favour of liberalising Ireland abortion laws was deeply resented by many - it has deteriorated since the general election, and the formation of government.
While Ó Cuív has indicated that he does not intend to table a motion of no confidence in Mr Martin, the topic of the leadership is now frequently privately debated among Fianna Fáil TDs and senators in Leinster House.
However, allies of Mr Martin point to the fact that he secured the backing of three quarters of the party membership for the coalition deal with Fine Gael and the Green Party.