The Labour Party has selected former minister for communications Alex White as its Dublin candidate for the European Parliament elections.
The elections, which will be held on 24 May, will see the number of seats in Dublin increase from three to four.
Labour last won a seat in Dublin in 2009 when Proinsias De Rossa was elected.
Fianna Fáil is set to select its candidate for the constituency within the next four weeks.
Those hoping to win the nomination include former ministers Mary Hanafin, Barry Andrews and Conor Lenihan, and marriage equality campaigner Tiernan Brady.
Sitting Sinn Féin MEP Lynn Boylan is set to contest the May election, but Fine Gael's Brian Hayes and Independent Nessa Childers are not running again.
Super Junior Education Minister Mary Mitchell O'Connor has not ruled out seeking the Fine Gael nomination.
"I am keeping my options open. But my focus is and has been on my Department for Higher Education and on my constituents and constituency," she told RTÉ News.
The Green Party has selected the former junior minister Ciarán Cuffe to run in Dublin, where party leader Eamon Ryan came close to winning the last seat in 2014.
Éilis Ryan of the Workers’ Party is also contesting the European Parliament elections in Dublin, while north inner city councillor Gary Gannon is seeking to run for the Social Democrats.