Opposition: Opposition parties welcomed the preliminary census findings as a positive indication of the State's economic growth but said the figures reflected poorly on the Government's approach to regional development and planning.
Fine Gael's spokesman on Enterprise, Trade and Employment, Phil Hogan, said the results, which showed "the true scale of urban sprawl in Ireland", should act as "a wake-up call" to the Government.
"Despite a very welcome growth of 8 per cent in the national population in the last four years, the figures for Dublin city, Limerick city and Cork city are a cause for worry," he said.
Though the population of Dublin city rose by only 2 per cent between 2002 and 2006, he said, there was "huge population growth" in neighbouring Fingal (22 per cent), Meath (21 per cent) and Kildare (14 per cent). Similar situations prevailed in Cork and Limerick.
"This is clearly because young families simply cannot afford to buy a house close to the city and are forced into outlying areas, putting heavy strain on transport links and infrastructure.
"These patterns are not sustainable. While we must push for balanced regional development, and a move away from large urban centres like Dublin, we cannot have hundreds of thousands of people crammed into neighbouring areas commuting very long distances every day."
Labour party leader Pat Rabbitte said the figures highlighted the challenges the next government would have to confront. "These include real efforts to secure balanced regional development, advance provision of schools, better planning for youth and sport facilities, and a more proactive approach in planning public services to match population trends."
While the continuing growth of the greater Dublin area was welcome, the Labour leader said, it pointed to the failure to adequately provide for more balanced regional development.
"Building housing is not the same as building communities. As large numbers of people move into new areas, they have needs for medical services, for youth and sport facilities, and for community development," Mr Rabbitte said.
"Our systems of Government at national and local level seem incapable of responding to these needs."
These were challenges which the alternative government is ready to embrace, while "it is amply clear that they will not be addressed by a tired and out-of-touch FF-PD administration," he said.
The Green Party welcomed the findings' indications of economic growth.
Party leader Trevor Sargent TD said the shift in population confirmed Ireland's place among the most prosperous countries in the world but he urged politicians to put aside their arguments over electoral boundaries and focus on "the real issues" instead.
"Increased population clusters around the capital throw up many challenges, such as integration for the migrant population living there and the impact on the environment that extra housing and traffic congestion bring.
"The cluster also demonstrates how the Government has failed to bring about a proper regional development strategy. While the east coast is struggling to provide an adequate number of schools, the west coast is dealing with school closures.
"As migration shifts ever firmly to the east, the Government must concentrate on redevelopment of the rest of the regions.
"Opening up the Western Rail Corridor, for example, could bring massive growth to the area," Mr Sargent said.