Changes to constituency boundaries announced yesterday provoked a mixed response from politicians and political parties yesterday.
The biggest opposition to the changes came in Leitrim, where campaigners have been lobbying for several years to ensure their county is represented in a single constituency.
Cormac Ó Súilleabháin, a founder member of the Save Leitrim Campaign, said their position was now even worse.
"By taking about 3,000 people out of south Leitrim, the most populated part of the county and putting them in with north Leitrim, they have ensured that neither half of the county has enough voters to get a candidate elected," he said.
Mr Ó Súilleabháin said that while 241 of the 330 submissions related to Leitrim, the Constituency Commission had ignored the many different suggestions made and had dreamt up something which no one wanted.
"It beggars belief," he said. "It makes you realize there is no point in making a submission, when you come up against a brick wall after campaigning for three years".
Green Party TDs yesterday privately expressed concern that the changes may make some of their seats vulnerable, especially those of Ciarán Cuffe and Trevor Sargent.
However, Mr Cuffe - who narrowly won the final seat in the five-seat constituency of Dún-Laoghaire-Rathdown - said the Greens would campaign hard to retain their seats and win new ones in the next election.
One former TD likely to benefit from the changes, however, is former Socialist Party TD Joe Higgins. Mr Higgins narrowly lost out on a seat in the three-seat Dublin West constituency. However, the area will gain a seat as a result of the changes. Parts of Dublin North will also be transferred to Dublin West.
However, he was "deeply unhappy" at changes which "flew in the face" of natural geographical boundaries, in particular the transfer of parts of Dublin North into the constituency.
Re-drawing the boundary splits up the stronghold of his Socialist Party colleague Clare Daly in Dublin North.
The Constituency Commission's decision to reduce Dublin representation in the European Parliament by one seat drew sharp criticism from Fine Gael MEP Gay Mitchell.
The commission reduced the number of seats in Dublin from four to three, without altering the existing boundaries. Under the terms of the EU reform treaty, Ireland is due to lose a European seat. "It is very difficult to understand how the commission arrived at this proposal," Mr Mitchell said.
"The effect of this is that each MEP will represent only 331,000 people in the East constituency, 332,000 in Ireland North West and 355,000 in Ireland South. In Dublin, each MEP will represent almost 396,000 people," he said.
Mr Mitchell added that Dublin MEPs will represent almost 65,000 more people than in the East or North West, a disparity of 18 per cent.