One of the groups opposed to the route of the M3 motorway being built near the Hill of Tara in Co Meath has called for a new Environmental Impact Assessment to be carried out.
TaraWatch has said it wants Minister for Environment John Gormley to order a new one, before the construction work becomes irreversible.
The national monument has been voted one of the top 10 discoveries of 2007 by the Archaeological Institute of America
In a separate development, Dr Conor Newman who was appointed by the Government to oversee the proper excavation of the site, has stepped aside.
Mr Cronin has criticised the Government, accusing it of ignoring expect advice about the significance of the monument.