Four members of An Taisce held a sit-in at the Presbyterian church on Adelaide Road, Dublin, at the weekend, in protest at the demolition of part of the structure. Mr Ian Lumley, heritage officer with An Taisce, claimed the work was in breach of planning regulations, which must be met before development can begin.
An Taisce is seeking an order under Section 27 of the Local Government (Planning and Development) Act, 1976, requiring the work to be halted.
A spokesman for Dublin Corporation said planning permission for the church was subject to compliance with a number of issues, some of which are "still outstanding".
These include the building of a sample of bricks on site, to give an idea of the appearance of the finished structure, and details of the window design. Work continued on Saturday. The Presbyterian Church, which is developing the site, said it had complied with all regulations.
"As far as the church is concerned, every stipulation has been met," said the Rev Frank Sellar, who was been a minister at the church for 10 years.
Planning permission, which was granted in 1996 and amended in 1999, refers to the demolition of the building behind the church's facade and its replacement with a new church, community hall, creche and ancillary facilities.
The church's original facade, railings, steps and portico are listed as protected structures, and will all be retained, said the corporation spokesman. The church, which was originally designed in 1840, is of great importance to the city's architectural heritage, said Mr Lumley. Demolition and rebuilding is also harmful to the environment, he said.
Mr Lumley and three members of An Taisce's National Council - Mr Tony Lowes, Mr Sean English, and Mr James Kelly - occupied the church at 1 p.m. on Saturday.
The decision to retain only the church's front is "ridiculous", said Ms Eileen Ross, a local resident and member of An Taisce. "It's just facade architecture - like Disneyland."
The church architecture committee of the Presbyterian Church in Ireland said "the present building, while interesting, is unremarkable architecturally as there are numerous examples of barn-type churches throughout Ireland".
The committee said the organ, pulpit and memorial windows, in keeping with amendments to planning permission, would be retained and incorporated into the new multipurpose auditorium.