Sinn Féin president Gerry Adams, who is planning to stand for election in Louth, has resigned from his Westminster seat.
The announcement came after Taoiseach Brian Cowen confirmed March 11th as the date for the general election.
Mr Adams had already stepped down from his West Belfast seat in the Northern Ireland Assembly and was replaced by former IRA hunger striker Pat Sheehan.
A party spokesman said Mr Adams has now written to Westminster to formally resign his seat and a candidate has yet to be selected to defend the seat.