Fianna Fail believes it has a "sound legal basis" to issue a gender diktat ahead of the party's selection convention in Dun Laoghaire, the Herald has learned.
Senior party figures are now firmly of the view that former minister Mary Hanafin should be the party's sole candidate to contest the three-seat constituency.
The matter has been discussed at length among Fianna Fail top brass in recent days amid accusations that the party is responsible for "gendermandering".
On the back of claims by councillor Cormac Devlin that he will legally challenge any gender diktat, the party has sought its own legal advice ahead of Monday's convention.
"We have a sound legal basis for what we have to do," a senior party source said last night. "There should be one candidate, and that is Mary Hanafin.
The comments are the clearest indication yet that the party is preparing to direct the selection convention to select a sole female candidate.
Party strategists believe Ms Hanafin will defeat council colleague Kate Feeney and, therefore, represent the party as its sole candidate.
Ms Feeney told the Herald that she will back any decision by Mr Devlin to launch a legal challenge against a gender ruling.
Responding to a threat from Mr Devlin that he is considering mounting a challenge against any form of "gendermandering", Fianna Fail leader Micheal Martin said he does not foresee a scenario involving legal action.
"We've had no legal cases to date," he said. "In the context of conventions, people will be arguing their position, but I don't see any necessity for that kind of action."