Two of the 43 Dáil constituencies are to lose a seat each and two will gain a seat under changes recommended today by the Constituency Commission.
Louth will become a five-seater, increasing its number of Dáil seats by one.
The Dublin West constituency, currently a three-seater, will also gain one to give it four TDs at the next general election. Under the recommendations, there will also be changes in the bourndries of these constituencies.
Two five-seat constituencies, Dún Laoghaire and Limerick East, will lose one seat each bringing them to four. Limerick East will also be renamed as Limerick City. Boundary changes have also been recommended in these constituencies.
The Constituency Commission Report 2007also recommends revisions to 20 other constituencies: Cork East, Cork North-Central, Cork North-West, Donegal North-East, Donegal South-West, Dublin North, Dublin North-Central, Dublin North-East, Dublin South, Kerry North, Kerry South, Kildare North, Kildare South, Laois-Offaly, Limerick West, Meath East, Meath West, Roscommon-South Leitrim, Sligo-North Leitrim and Tipperary North.
Today's report says total Dáil membership should remain at 166 TDs, arranged in 43 constituencies.
The report presented to Ceann Comhairle John O'Donoghue, is aimed at maintaining an equitable representation of TDs in every part of the State based of last year's population census.
Current Dáil constituencies are based on the 2001 Census.
Major changes had been expected given that population changes have significantly affected the TD-to-population ratio in almost half of the 43 Dáil constituencies.
Some of the biggest changes have been made in Dublin and surrounding counties Kildare and Meath, where population changes have been greatest.
Dún Laoghaire-Rathdown was one constituency that was over-represented in the Dáil and, as expected, it lost a seat under the recommendations today. Kildare South had been expected to gain a seat.
On European Parliament constituencies, the Commission has recommended a reduction of one seat in the Dublin constituency and the transfer of the populations of Longford and Westmeath from the East to the North-West constituency. This is in the context of a reduction in representation to 12 MEPs.
The commission, which was established under law by the Minister for the Environment this year, received 173 submissions from political parties, politicians and citizens over the summer.
Under the Constitution, the number of TDs in the Dáil shall not be fixed at less than one for each 30,000 of the population, or at more than one member for each 20,000 of the population. The ratio between the number of members elected in each constituency, based on the last census, should also be the same throughout the country "so far as it is practicable".
Two politicians and a Dublin West constituent took an unsuccessful High Court challenge earlier this year in relation to the manner in which the electoral constituencies had been revised.
In May, Mr Justice Frank Clarke dismissed arguments that the Oireachtas had breached the Constitution in how the constituencies were revised. However, he also stressed the need for the Oireachtas to move speedily to address "impermissible variations" existing in several constituencies relating to the number of TDs per capita of population.