Keaveney switches to Fianna Fail
Colm Keaveney, a TD for Galway East, had first rebelled when he refused to support Budget 2013 last year and then resigned from the party in the summer.
He said he was opposed to some of the reforms in the new abortion legislation.
In a short statement, Fianna Fail confirmed that Mr Keaveney has applied to join Fianna Fail.
The Fianna Fail parliamentary party will discuss the prospect of taking on the former Labour man at its weekly meeting in Leinster House this afternoon.
Mr Keaveney has caused the Labour hierarchy headaches for several months after refusing to support the budget but remaining on as the chairman.
In his resignation from the party he accused the coalition of targeting cuts at those least able to defend themselves.
He said he was becoming more alienated the more he tried to promote Labour values.
It is understood he is being offered a front bench position in Fianna Fail and will become their 20th TD.
Labour has lost a string of representatives since it took its biggest electoral success in early 2011.
Former junior health minister Roisin Shortall quit after clashing with Health Minister James Reilly over the designation of primary care centres in his constituency.
Patrick Nulty was kicked out of the parliamentary party after voting against the coalition's first budget in December 2011.
Nessa Childers MEP quit in April, claiming the party was hurting people.