The Office of Public Works has sent a strongly worded letter to planners in Co Louth outlining concerns about an application to build the country's first eco-friendly hotel on part of the site of the 1690 Battle of the Boyne at Tullyallen.
Eugene Keane of the heritage services division said the application was "premature" and the 23- bedroom four-star hotel is proposed for "a significant historic part of the site of the Battle of the Boyne, the most important battle site in Ireland".
It is also adjacent to where King William was wounded by a cannon shot and is opposite the 18th century Obelisk Bridge erected to mark the historic event.
The application by businessman Gavin Collins proposed using a wood-pellet heating system, solar panels and recycling of grey water and said the hotel was designed to be eco-friendly and also to "become part of the interactive heritage facilities in the area".
It proposed what is described in the planning application as "a prime viewing platform over the Battle of the Boyne site".
The OPW is developing a visitor and exhibition centre, new walkways and a peace garden at the site. When it is completed in about two years, the Government will have spent €30 million on purchasing the 500-acre Oldbridge estates, house and works on it.
"Work is in progress on this significant heritage and tourism project which will attract an estimated 100,000 visitors annually and deliver benefits over a wide region in Louth and Meath," Mr Keane said. "The project is predicated on maintaining the high visual quality of the historic landscape".
The OPW said the planning application was premature "in the absence of a detailed planning strategy for this highly sensitive area and may establish an undesirable precedent".