Almost €30m has been spent so far on archaeology for the controversial M3 motorway near Tara where protesters have tunnelled in to hold up work.
This is one-tenth of the entire €300m earmarked for archaeology costs on the entire national motorway programme, the Irish Independent has learned.
The war of words continued yesterday between protesters, who have occupied tunnels they secretly made beside the Rath Lugh protected monument, and the National Roads Authority.
The Save Tara campaign group said yesterday that a young woman has vowed to seal herself into one of the tunnels to protect the hill, which is studded with ancient earthworks.
The hill is sitting on top of an esker, a collection of soil, sand and gravel. The group opposed to the motorway running near the Hill of Tara claimed that because of the fragile nature of the soil in Rath Lugh, any movement of heavy machinery in the vicinity of the Rath would collapse the tunnel, "with possible fatal consequences".
"Any eviction attempt . . is likely to end in failure, with possible catastrophic consequences.
"There are specialist tunnel rescue crews that need to be consulted before any attempt is made to end this protest," said the group.
The NRA says the new road, now costing more than €1bn, will be further away than the totally gridlocked old road and insisted it would not damage the Rath Lugh monument.
The authority has said the new motorway will be far safer than the existing road, which is 50pc more dangerous on average that other main roads.
An NRA statement yesterday said there was a preservation order on the monument at Rath Lugh and "at no point are we encroaching on the monument".
It said the contractor was putting in place a crib wall within the footprint of his work area to guarantee there will be no encroachment.
The NRA claimed that protesters were taking apart protective fencing and were digging on the site itself "causing impact on the area".
The authority said the motorway would be further away from the Hill of Tara than the existing N3 road.
The M3 motorway via Meath and Cavan has been delayed for years.
A spokesman for Environment Minister John Gormley said that an independent engineering report he commissioned after concerns were raised about possible damage to Rath Lugh had recommended a series of extra measures to protect the area.
These recommendations had been passed on to the NRA, said the spokesman for Mr Gormley.