The co-director of Ashcastle Developments, the company refused planning permission by An Bord Pleanála to build 53 luxury apartments and a public park beside Booterstown Marsh bird sanctuary, has said the board's decision is "not the end of the road".

"We are a little disappointed but there were a lot of positives in the inspector's report and we intend to look at our options," said David Jameson.

An Bord Pleanála's decision overturned planning permission granted by the two local authorities with jurisdiction over the 4.5-acre site. Two-thirds of the site is in the administrative area of Dublin City Council, which granted planning permission for 53 apartments in four blocks.

Dún Laoghaire-Rathdown granted permission for a public park, landscaping and a 14-space public car-park. Planning permission to develop beside Booterstown Marsh, which is a significant wildlife reserve visited by redshanks, herons, kingfishers and snipe, proved controversial locally and was appealed by three parties, including An Taisce, which owns the marsh.

The developer responded to appeals by saying it was ceding 70 per cent of site to the local authority for public use and contended the eco-system of the bird marsh would not be adversely affected. It said the public park would not be manicured but would be preserved as a semi-natural environment and the development would not detract from listed views in the area or prejudice plans for an eastern bypass.

An Bord Pleanála refused planning permission on the grounds that the scale of the development would materially contravene the site's zoning in the Dublin City Development Plan "to preserve and provide open space and recreational amenity".

It also ruled the development would be premature pending future development of an eastern bypass route for Dublin city.

Ashcastle bought the reclaimed site in 1998 and a year later withdrew a planning application for 120 apartments in a number of blocks dotted around the site.