Legal submissions ended yesterday in the High Court challenge to the M50 motorway at Carrickmines Castle, and Ms Justice Laffoy will make her decision on the case next Tuesday.
The State yesterday concluded its defence of the constitutional challenge to the south Dublin portion of the South Eastern Motorway taken by Dublin conservationist Mr Dominic Dunne.
He claims part of the National Monuments Amendment Act, 2004, is unconstitutional and contrary to EU directives.
The Act was introduced earlier this summer.
Section 8 of the Act allowed for the partial demolition and removal of the ruins of Carrickmines Castle to allow for the construction of the South Eastern Motorway - the final link in Dublin's M50 bypass.
Dún Laoghaire-Rathdown County Council was ordered to stop work on the controversial M50 route on August 19th to facilitate a full High Court hearing into the legality of the new heritage legislation.
Work will not be resumed on the south Dublin site until Ms Justice Laffoy delivers her judgment next Tuesday afternoon.
Lawyers for the Attorney General, Mr Rory Brady, and the Minister for the Environment, Mr Cullen, have said the State believed it was acting entirely within the law.
They also argued that the State never intended to do any damage to the stone fortifications of the medieval castle, while building a section of the motorway over the site.
The constitutional challenge to the south Dublin portion of the €596 million South Eastern Motorway is costing more than €350,000 a week, according to council officials.
They have expressed their disappointment that, once again, the completion of the M50 at Carrickmines has had to be put on hold.
The project was previously dogged for two years by sit-in protests and legal battles.
The motorway was to open to the public by October 2004 but, as a result of delays, that date has now been extended to August 2005.
Conservationists, however, have accused both the National Roads Authority and the council of exaggerating the costs of the delays brought about by the various court cases.