Fine Gael TD John Perry is to launch a High Court action against his own party on Thursday.
Mr Perry is the outgoing TD in Sligo-Leitrim, but lost out at the selection convention for the constituency ahead of the general election in a close contest.
Mr Perry confirmed that he is to seek an injunction to stop Fine Gael from ratifying the election ticket in the constituency.
In a statement, he said he was making the move on behalf of ordinary party members and criticised the behaviour of those in charge in Dublin.
Mr Perry will also seek to prevent Fine Gael taking any further steps to nominate other candidates to stand for election in the constituency.
Mr Perry has campaigned for a number of weeks to be added to the ticket, and made a number of pleas to Taoiseach Enda Kenny.
Allegations
The former Minister of State is claiming that some Fine Gael members were unfairly barred from voting for him.
He also alleges the Taoiseach had promised all outgoing TDs that they would have the chance to retain their seats.
Mr Perry, a TD since 1997, Tony McLoughlin, and former deputy Gerry Reynolds contested the convention in October.
The result saw Mr Reynolds and Mr McLoughlin selected.
Fine Gael has said it stands by the result at the convention.