COALITION TDs in a number of key constituencies will be in a fight for survival due to sweeping boundary changes and a smaller Dail.
The Constituency Commission has recommended the redrawing of lines, most notably in Dublin.
Dublin Central has been reduced from four to three seats, with Fine Gael's Paschal Donohoe hit by the loss of the Navan Road, Ashtown and Drumcondra.
The number of seats in Dublin South -- to be renamed Dublin Rathdown -- has been slashed from five to three, placing Labour's Alex White and Fine Gael's Peter Mathews under pressure.
Dublin South is to lose nine electoral divisions to Dublin South West, which will become a five-seater.
The next Dail will only have 158 TDs, down from 166, while the number of constituencies is dropping from 43 to 40.
The five-seater Dublin South Central is to lose a TD as the whole of Terenure is subsumed into Dublin South East, to be renamed Dublin Bay South.
Labour's Eric Byrne, who lives in Terenure, and Michael Conaghan, will be most affected, it is thought.
Fine Gael had promised to cut the number of TDs by 20 but the recommendation from the Commission was for a reduction of eight.
Dublin North Central and North East are to be merged into the five-seater Dublin Bay North, losing one TD.
The two areas are currently represented by three Labour and two Fine Gael TDs as well as the Independent Finian McGrath.
Dublin North, to be renamed Dublin Fingal, will get an extra seat to become a five-seater as Swords is added, gaining 26,000 voters.
Dublin West remains a four-seater.