Lucinda Creighton says she will not be renewing her Fine Gael membership this week.
The former Minister for European Affairs has told the Irish Independent it is 'time to move on'.
There has been speculation that she will form a new political party in the future, because of her involvement with the Reform Alliance.
The former Junior Minister was expelled from Fine Gael last July for voting against the government on abortion legislation.
Opinion polls
Meanwhile, Fine Gael's MEP for Ireland South, Sean Kelly, has told Newstalk's Pat Kenny show he is disappointed by this morning's Millward Brown opinion poll in the Irish Independent showing both government parties dropping in public popularity.
Mr. Kelly, whose personal popularity rating dropped. At 12% of the vote he is in danger of losing his seat.
The MEP wants his supporters to understand that the notion that 'Sean Kelly is safe has been dispelled':
The same opinion polls have caused disquiet in the Labour party, with Phil Prendergast - also in Sean Kelly's constituency - dropping to 4% and subsequently calling for a change in the leadership of her party.