Planning approval for a major retail and residential development in Dungarvan, Co Waterford, has been appealed to An Bord Pleanala by An Taisce.
Supporters of the development, on nine of the 40 acres of the former Glanbia site, say it will transform the town centre and attract shoppers from other areas.
The proposal by Clancy Construction, which was approved last month by Dungarvan Urban District Council, would give the town its first major shopping centre, with Dunnes Stores as the anchor tenant.
A restaurant/night-club, residential units and a cinema complex are included in the first phase.
An Taisce claims, however, that it would be "an injustice, both to the people of Dungarvan and Co Waterford and the proper development of the site" to allow the scheme to proceed.
In its appeal to An Bord Pleanala, the organisation's heritage officer, Mr Ian Lumley, says the Glanbia landholding is one of the largest vacant industrial sites adjoining any Irish town, making this a major opportunity to achieve an urban model in sustainable development and design quality.
He claims the scheme as proposed, which includes extensive surface car-parking, would damage other retail businesses in the town.
Retaining the industrial shed building on the Glanbia site as a supermarket would be "uneconomic and inappropriate", he argues.
"It is a mistake which has been made in many developments in Ireland, where shedlike supermarkets have failed to be designed as integrated developments which, for example, could carry car-parking at a lower level in order to achieve better site use and mitigate the level of surface carparking required."
The development, he claims, would be "just another suburban supermarket grafted on to the edge of the existing town and developed at the expense of the existing business".
Many local businesses, however, are in favour of the scheme, which has the support of Dungarvan Chamber of Commerce. It believes the development will bring custom, currently lost to Clonmel, Cork, Waterford and other urban centres, to the west Waterford town.
Dungarvan's town clerk, Mr Brian White, denied Mr Lumley's claim that the scheme contravened the UDC's recently adopted development plan.