The National Roads Authority (NRA) may oppose the Ikea superstore proposed for Ballymun in north Dublin.

Mr Peter Malone, the chairman of the road building agency, has warned that the NRA is concerned the development will add further to congestion on the M50 motorway.

The NRA is currently reserving its position as "there is nothing to oppose" at this stage, according to Mr Malone.

But the Swedish-owned furniture retailer is expected to lodge a planning application by the summer. It follows the relaxation earlier this year of the planning guidelines to allow the one-off development of large stores in designated areas.

The application will be supported by Ballymun Regeneration, the Dublin City Council agency responsible for redeveloping the area which has a history of deprivation. Ballymun Regeneration owns the 90 acre site on which it is proposed to build the 28,000 sq m store.

Mr Malone said that the development could compound congestion on the motorway, much of which is due to previous planning errors.

"The problem with the M50 is that the planning is wrong. There are to many shopping centres and apartment complexes," he said.

He added that somewhere like Portlaoise would be a far more suitable location for such a project. In a few years, the midland's town would be connected by motorway to all the major urban areas, he said.

Mr Malone added that the contract for the major upgrade of the M50 would shortly be awarded and the NRA had started some very preliminary work on a outer ring motorway for Dublin.

The Taoiseach, Mr Ahern, flagged the project in a speech this week at the sod-turning for a new development at Adamstown in west Dublin. Mr Ahern pointed towards demographic trends and the desire of people to live in the greater Dublin area as factors driving demand for an outer ring road.

Mr Malone said that the authority expected to be formally asked to look into the feasibility of such a project by the Taoiseach.

He said that the project would not form part of the NRA's programme for 2009-2014, which are being finalised. Details of the five-year programme will form part of a 10-year infrastructural envelope, due to be announced by the Minister for Transport, Mr Cullen, later this year.

One issue that would have to be looked at would be a levy on developments in the vicinity of the proposed outer ring, said Mr Malone.