Without a national strategy to secure more balanced regional development, the Greater Dublin Area could reach a population of 2.4 million by 2020, according to a senior official of the Department of the Environment.
Mr Finian Matthews, principal officer in charge of the team preparing a national spatial strategy, said this scenario would mean most other regions would grow only marginally and some, such as the midlands, would lose population.
Addressing the opening session of the National Housing Conference, jointly organised by his Department and the Royal Institute of the Architects of Ireland, Mr Matthews said the Greater Dublin Area (GDA) would have to absorb an extra 800,000 people.
But if even 8 per cent of projected growth in employment was located elsewhere, "not only could we stabilise the GDA's share of national population at its present level of around 40 per cent, but we could also see substantial growth in the regions".
Even under this more benign scenario, he said the area - which includes Meath, Kildare and Wicklow - would still grow by almost half a million, to about 1.9 million in 2020, "driven largely by its own social and economic momentum".
But there would also be stronger growth in the regions, with the south-west increasing by almost 250,000 people, the midwest by 126,000 and the midlands by 54,000. The population of rural areas would also be stabilised, Mr Matthews said.
Giving a firm indication of where growth might be directed under the strategy, which is to be submitted to the Government later this year, he suggested Cork would grow by 75,000, Galway by 23,000, Limerick by 69,000 and Waterford by 11,000.
Apart from the main cities, the strategy will also target growth to a series of "gateway" towns which have the characteristics necessary to attract investment and develop "critical mass", in line with the National Development Plan.
But Mr Matthews said "gateways" were only part of the story. Their development would need to be linked to other medium-sized towns to act as "hubs of economic growth" for the surrounding areas.
Though this regional development strategy was "very much a skeleton of a possible way forward", he told the conference that a framework paper setting out the various options for a national spatial strategy would be published in early summer.
