FINE Gael MEP Mairead McGuinness faces having to go west to look for votes as her base is likely to be split in a redraw of the European map.
Ireland is expected to lose a European Parliament seat next year, dropping from 12 to 11 MEPs, as a result of new rules and the expansion of the EU.
The likely outcome of a necessary redraw would be the existing Ireland East constituency of Leinster being split between Ireland North and West, already covering Connacht, Ulster and parts of Leinster and Munster and Ireland South, made up of most of Munster.
Although an official decision on MEP numbers has yet to be taken, ministers are expecting Ireland's allocation to be cut. As a result, a boundary commission will have to be set up by the Government this summer to draw constituencies with a relatively even spread of MEPs.
"It looks like we'll lose a seat. You'll be down to three constituencies," a coalition source said.
Ms McGuinness will be the most affected by the redraw as her north Leinster base will split and potentially even be dragged in three directions. The counties of Louth, Meath and Kildare could conceivably end up in three separate constituencies.
She would probably end up in an Ireland North and West constituency, which takes in Connemara in Galway to the Cooley Peninsula in Louth.
On the plus side, getting elected in such a large constituency would boost Ms McGuinness's prospects in the next Presidential election – if she chose to run again.
The new constituencies will move even further away from the traditional divide along provincial lines.
The options in a redraw are a large five-seat constituency and two three-seaters or two four-seaters and a three-seat constituency.
Dublin is so big, with a population of 1.3 million that it would be unlikely to broken up, although there would be the possibility of any in nearby commuter belt counties for a Greater Dublin area constituency.
A more likely scenario is leaving Dublin untouched with three seats, as it already has the largest proportion of people to MEPs – 10pc above the national average.
The remaining eight seats would be divided between the rest of the country in two constituencies.
Under the Lisbon Treaty, the number of MEPs must be reduced to 751 after the 2014 European Parliament election – a reduction of 15 seats. Although there are currently 754 MEPs, Croatia's membership this year will add another 12 MEPs.
No country is allowed to have more than 96 seats, so Germany's numbers will be cut by three from 99.
Ireland is one of 12 countries set to lose one seat each, along with Romania, Greece, Belgium, Portugal, Czech Republic, Hungary, Austria, Bulgaria, Lithuania, Latvia and Croatia.