The High Court has dismissed claims by two politicians that a number of electoral constituencies were unconstitutional in the run-up to the general election.
The case was brought by Independent TDs Finian McGrath and Catherine Murphy after they examined census figures.
Using population statistics from the Central Statistics Office, the pair claimed 10 constituencies were unconstitutional due to dwindling numbers in rural areas and booming migration to greater Dublin.
The pair, who brought the case a month before the election was called, argued that there are not enough TDs for growing populations and that democracy is being eroded as a result.
Under article 16 of the 1937 Constitution, the number of TDs in the Dail should not be less than one for each 30,000 of population, nor more than one for each 20,000 of the population.
They claimed five constituencies were under-represented - Dublin West and North, Meath East and West and Laois-Offaly.
Five others were over-represented, they say - Cork North Central, Dún Laoghaire, Kerry North and South and Dublin North-East.
Ms Murphy and Mr McGrath analysed population records from the CSO and claim 10 of the 43 constituencies breach rules on representation. They said Article 16 of the Constitution states that every constituency should have, within reason, the same ratio of TD per population.
Any electoral review is likely to last six months.
The action was taken against Environment Minister Dick Roche, who has responsibility for constituencies, and Attorney General Rory Brady.
Mr McGrath retained his seat at the election but Ms Murphy, who was elected to the Dáil in the 2005 Kildare North by-election after Charlie McCreevy was appointed an EU Commissioner, lost out on the last count to Fine Gael's Bernard Durkan.
Mr Justice Frank Clarke said today his dismissal of the case must be seen in the context of the "urgent" nature of the obligation on the Oireachtas to speedily move to remedy the "significant, disproportionate and impermissible" variations existing in several constitencies between the numbers to be elected to the Dáil and the numbers of population as found in the last census.
The ratio was more than 10 per cent beyond the average in a number of constituencies, the judge noted. In his view, he added, it was not possible to establish an "acceptable" level of deviation and the Oireachtas had an urgent obligation to reduce any disparity to an absolute minimum.
The judge said there should be "urgent consideration" of whether the Electoral Act 1997 should be amended to allow measures to begin from the time of publicaiton of preliminary rather than final census figures.
The fact an election may be called at short notice increased the obligation to act speedily, the judge said.
It was not practicable between the publication of the final census figures on March 29th and the point when the Dáil was disssolved on April 29th to ensure the process of enacting amending legislation was completed in time for the general election.
Minister for the Environment Dick Roche welcomed the decision of the High Court.
Mr Roche said that following the publication of the final census results he had established a Constituency Commission to undertake a review of Dáil and European constituencies.
"The Commission is required to report to the Chairman of the Dáil no later than six months from the date of its establishment," Mr Roche said.