Mr Michael McDowell of the Progressive Democrats has topped the poll in Dublin South East, based on tallies with all ballot boxes open.
Mr McDowell has beaten Fianna Fail's Mr Eoin Ryan, Mr John Gormley of the Green Party and Labour Party leader Mr Rúairí Quinn. Ms Frances Fitzgerald looks set to lose her seat in Dublin South East.
Mr McDowell's apparent success highlights a trend in strong PD support. PD candidate, and former IFA leader, Mr Tom Parlon is putting up a strong showing in Laois Offaly, where Minister for Foreign Affairs Mr Cowen is expected to comfortably top the poll.
The Tánaiste Ms Harney, in Dublin Mid-West, and Ms Liz O'Donnell in Dublin South are expected hold their seats for the PDs, while in Dún Laoghaire Ms Fiona O'Malley is tallying well.