The cross-Border heritage and environment organisation "The Battle for the Boyne" has accused the Government of "butchering the Boyne and democracy".
The group accused the Coalition of "effectively sponsoring" the destruction of the Boyne Valley and of displaying "an appalling attitude towards some of Ireland's most precious heritage".
Spokesman Mr Brian Hanratty cited plans for what will be the country's first municipal waste incinerator at Carranstown, Co Meath, which is adjacent to the boundary of the Boyne Valley, a World Heritage site, and the proposed route of the M3 motorway which is due to run close to the Hill of Tara.
"The Minister for the Environment, Martin Cullen, and his Government colleagues try to hide behind An Bord Pleanála and the National Roads Authority to avoid criticism when the reality is they set the ground rules for these organisations," he said.
"Martin Cullen took Dúchas - the Heritage Service - into the control of his Department and the Minister himself, rather than professional archaeologists, now dictates what planning cases Dúchas are allowed to appeal," Mr Hanratty went on.
He also claimed that Fianna Fáil and the PDs were creating policy on planning and waste management, and as a result no local government decisions were being taken on such issues.
Meanwhile, a report by a UNESCO delegation that travelled to the Boyne Valley in February to meet opponents of the incinerator will be presented to the 28th session of the World Heritage Committee when it meets in China later this month.