Minister for the Environment Dick Roche's insistence that any decision by him to refuse licences for archaeological excavations along the route of the M3 motorway would be an abuse of his powers has been described as an "outrageous distortion".
Labour TD Michael D Higgins, who was minister for arts and heritage between 1992 and 1997, said that the National Monuments Acts explicitly provided for the exercise of such ministerial discretion even after a major road project is approved.
"Dick Roche is outrageously wrong in his interpretation of the legislation that I introduced as minister in 1994," Mr Higgins told The Irish Times.
"Indeed, it's explicit that the Minister's role comes into effect after the planning process."
He said Mr Roche's claim that he could not "revisit" An Bord Pleanála's decision in August 2003 to approve the M3 was an "outrageous distortion" of the provisions of the 1994 National Monuments Act, and even of its amendment in 2004.
The legislation enacted in 2004, on foot of the Carrickmines case, made it clear that it was "at the discretion of the Minister" whether he issued his consent, and also that he was entitled to consider the public interest in making a decision.
The possibility of altering the route of an "approved road development" was also provided for under Section 14 of the 2004 Act, which laid down that any such alteration must be referred to An Bord Pleanála to determine if it was "material".
If the board determined that it was "as a consequence of the directions of the Minister", it could then require the submission of a revised environmental impact statement "for the purposes of permitting any changes to the route", the Act says.
"I introduced the requirement that the director of the National Museum must be consulted before any directions were issued in relation to the treatment of archaeological sites," Mr Higgins said.
"And that was just one of the safeguards."
He added: "The legislation I introduced also provided that where there was conflict between the minister for the environment, who had responsibility for roads then, and the minister for heritage, that the issue would go to the cabinet to resolve."
Mr Higgins said he had always believed that "Philistinism would rule" after heritage functions were transferred to the Department of the Environment in 2002 and the subsequent decision to abolish Dúchas, the heritage service.
He described the plan to run the M3 past the Hill of Tara as "absolutely disgraceful".