The Government has asked the Attorney General to examine the preliminary Census report which shows one Dáil constituency in breach of the constitutional population guidelines.
The Labour Party has called for the constituencies to be reviewed, but the Minister for the Environment, Dick Roche, has said this could not be done on the basis of preliminary results.
Preliminary figures from the 2006 Census show that the State's population has increased to just over 4.2 million.
This is the highest level since 1861 and represents an increase of more than 300,000 compared with 2002.
The figures show that in the last decade, the Republic's population has grown at an annual average rate of 1.6%, which is the highest rate in the EU.
Three areas - Fingal, Co Meath and Co Kildare - accounted for 30% of the increase since 2002.
The constituency of Dublin West had the highest number of persons per TD at 30,933, after recording an increase of nearly 27% in population since 2002.
But the Central Statistics Office describes the increase for Dublin as a whole as 'relatively modest' at 5.6%, well below the national increase of 8.1%.
Cork city and Limerick city were the only two of 34 administrative counties to record falls in the population in the last four years.