Ha'penny Bridge, linking northside and southside Dublin

Dublin is forecast to soon have a footprint the same size as Los Angeles with less than a quarter of its population, according to a report published today.

The Urban Forum says that with the Dublin population expected to grow by more than 1 million over the next 20 years, the development raises serious concerns for the health of people living in an ever-expanding Greater Dublin Area.

The Urban Forum is made up of Engineers Ireland, the Irish Landscape Institute, the Irish Planning Institute, the Royal Institute of the Architects of Ireland and the Society of Chartered Surveyors

The Forum warns that time-consuming commuting and a lack of facilities could lead to higher levels of stress, diabetes, heart disease and childhood obesity.

Ireland is already one of the most car-dependent countries in the EU and one of the most oil-dependent in the world.

The Forum says viable public transport based on light rail and high speed trains to counter the environmentally unsustainable low-density development of conurbations was needed. Outer suburbs were expanding while town and city centre were in decline, it noted.

It also expressed concern about an "explosion" in one-off houses, which it said accounted for up to 40 per cent of new stock.

Noting that 54 per cent of the population now live in Leinster, the Urban Forum said a counter-pole to the capital was required in the South and West and called for a review of the National Spatial Strategy (NSS).

The NSS according to critics proposes the development of too many relatively small urban centres rather than generating the "critical mass" of a city - which makes transport and other services such as hospitals and water more cost-effective.

At the publication of the policy document, A Better Quality of Life for All, Forum chairman, Henk van der Kamp, said: "The proper resourcing of our planning system and construction research will all be vital in order for Ireland to be in a position to deliver this vital infrastructure more effectively".

In January the Government published the National Development 2007 - 2013 which continued to promote the development of smaller hubs based around towns such as Tullamore, Sligo and Mullingar.

The Urban Forum called for large-scale development of the principal cities; Cork, Limerick and Galway to create and "Atlantic Gateway".

"The very fact that the NDP is increasing investment in infrastructure provision gives even greater urgency to some of our proposals," Van der Kemp said.

The group called for a national body with responsibility for construction research. It also proposed a Department of Urbanism at Government level and land use bodies to integrate transport and development plans for the Greater Dublin Area and other cities.

More planners and related personnel in local authorities to deliver quality planning and development of greenspace and recreational space was also needed.

The report also proposes that consideration be given to tax incentives encouraging people to occupy smaller and older houses instead of new homes.