Fine Gael MEP Simon Coveney is to seek a nomination to run in the next general election.
Mr Coveney is one of the party's high-profile figures and has been tipped as future leader of the party. He is a sitting TD but won a European Parliament seat in the South constituency in 2004.
Speaking to reporters at the Imperial Hotel in Cork, Mr Coveney said he made the decision for personal, professional and party reasons.
The decision, while not unexpected, is a significant boost to Fine Gael election prospects. Mr Coveney is all but certain to secure the nomination for the Cork South Central constituency, where he is a sitting TD, and the party will hope his appeal will return his running mate.
"If Fine Gael can achieve this in South Central I believe we will be playing our part in winning the extra seats required by the party to form a better government", Mr Coveney said.
He said the decision was difficult but he felt he could make a more significant contribution to public life as a Fine Gael representative at national level.
"In the next general election in Ireland I believe there is a real and genuine prospect of Fine Gael being elected to government with Enda Kenny as taoiseach . . . that prospective new Fine Gael Government is something I want to help bring about and be part of," Mr Coveney said.
Under EU rules a sitting MEP must give up his seat if he takes up a seat in a national parliament, but a by-election not required as a substitute can be nominated. Cork councillor Colm Burke was declared as Mr Coveney substitute after he he won the European parliament seat.