Conservationists will this morning lodge an application in the High Court for an interlocutory injunction to stop construction of the South Eastern Motorway over the ruins of Carrickmines Castle.
Yesterday Justice Michael Peart heard that new legislation allowing work to resume at the South Dublin site on Monday was "unconstitutional" and that a national monument "was being unlawfully destroyed as we speak".
The application was made this afternoon on behalf of Mr Dominic Dunne of Collins Square, Benburb Street, Dublin.
Mr Dunne is one of the original litigants that stopped work on the site last January after courts found it was unconstitutional.
Mr Colman Fitzgerald SC said that "excessive powers" were given to Environment Minister Martin Cullen under the new National Monuments Amendment Act 2004 and that this breached Article 15(2) of the Constitution.
The National Monuments Amendment Act, enacted in July, followed another successful legal challenge by the 'Carrickminders' conservation group last January.
The Act made specific reference to the M50 project and allowed Minister Cullen to make an order allowing for partial destruction of the Carrickmines site in order for construction work to continue.
Mr Fitzgerald said the resumption of work on the site also breached Article 5 of the Constitution which stated that the State has a duty to protect the national heritage of the people of Ireland.
Mr Justice Peart said that he had "limited knowledge" of the 18-month saga of sit-in protests and legal battles in relation to the issue.
He added: "What I know is what I have read in the morning's papers. But I know that the work is being carried out under the supervision of archaeologists."
The judge ordered Mr Fitzgerald to serve notice of his application to the respondents; Dun Laoghaire Rathdown County Council and the Chief State Solicitors Office tonight.
He said the respondents should be given enough time to submit affidavits on their own behalf. He fixed the hearing for 2pm today in the High Court.