Negotiations are taking place between the Department of the Environment and the conservationist Vincent Salafia in an attempt to resolve a dispute over the planned M3 toll motorway through Co Meath.
Mr Salafia, an activist with the Save Tara-Skryne Valley campaign, is taking a Supreme Court challenge to the motorway route, contending that it passes too close to the Hill of Tara, a national monument.
His High Court case was earlier dismissed by that court with costs estimated at about €500,000 being awarded against him. However, Mr Salafia has said he will take his case to the European Court if necessary.
Delays in building the motorway are currently costing €1 million a week and have already reached €70 million, according to the National Roads Authority (NRA).
Negotiations are under way between counsel for Mr Salafia and representatives of the Department of the Environment, Meath County Council and the NRA.
Neither the department nor Meath County Council would comment on the matter. A spokesman for the NRA said: "We look forward to a conclusion of all legal matters upon the courts being back in session."