Louth and Dublin West are to get an extra TD each under the recommendations of the Constituency Commission, published this afternoon.
Dún Laoghaire and Limerick East are both to lose a seat, with the latter constituency being renamed Limerick City.
Changes are to be made to the boundaries of another 20 constituencies, with two of them having their names changed.
Kerry North will be renamed Kerry North/West Limerick, while Limerick West becomes Limerick.
However there will be no change in the number of constituencies, which remains at 43, or the number of TDs, which will stay at 166.
The number of five-seat constituencies is reduced from 12 to 11, with the number of four-seaters increasing from 13 to 15, and one less three-seater.
The Constituency Commission's terms of reference required it to avoid breaching county boundaries if at all possible, and to maintain as much continuity as possible in the arrangement of constituencies.
However, the revision does involve three new breaches of county boundaries between Kerry and Limerick, Louth and Meath, and Offaly and Tipperary.
In Dublin, the Dún Laoghaire constituency loses one seat to become a four-seat constituency and also loses the area west of the N11 to five-seater Dublin South.
Dublin North loses parts of Swords and the area around Dublin Airport to Dublin West, which gains a fourth seat.
Portmarnock and Balgriffin move to Dublin North-East, which in turn loses Edenmore to Dublin North-Central.
Dublin to lose seat in Europe
For European elections, Dublin is to lose one seat to become a three-seat constituency, while Longford and Westmeath are to be transferred from the East to the North-West constituency.
Despite the revision, there is still a degree of variation in the ratio of population to TDs.
Under the new arrangements, Carlow-Kilkenny has the highest number of people per TD at 26,749, compared with the national average of 25,541, while Cavan-Monaghan has the lowest number with 24,000 people per TD.
The commission was appointed in April to update Dáil representation to meet the constitutional requirement to reflect population as established in the most recent Census.
Last year's Census showed there had been a massive and unprecedented change in the size and distribution of the Irish population since 2002.
The population grew in all but one of the 43 constituencies, but at a very uneven rate.
This left some areas like Dublin West and Dublin North under-represented when compared to Dublin South, Dún Laoghaire-Rathdown and Kerry South constituencies.
Review of constituencies
Environment Minister John Gormley has said he will bring forward legislation to implement the recommendations of the Constituency Commission in full and without amendments.
Minister Gormley said that previous Governments had introduced Commission recommendations without amendment, and it was his firm view that this should continue.
The legislation will also take account of a High Court ruling in a challenge to the last election being run with constituencies that did not take account of the most recent census.
Before the election, the Government argued there was not enough time to review the constituencies between the publication of the final census results and the calling of the election.
Under the new legislation, it will be possible to begin the constituency review on the basis of preliminary Census figures, although the review will not be completed until the final Census figures are published about a year later.
Sources in the Department of the Environment said that despite this change, it is highly unlikely that the constituencies will have to be revised again on the basis of the Census due in 2011, even if the current Dáil lasts its full five-year term, to 2012.
