Minister Gormley wanted to check out reports that the M3 works were impacting on the National Monument, and the 20 metre buffer zone, and satisfy himself that this wasn't so, a spokesman for his department said.
He visited the area on Thursday.
Mr. Gormley was satisfied that the motorway works were not encroaching on the site, the department said.
Nobber native archaeologist Professor George Eogan, has contradicted claims being made by the Minister for the Environment and the NRA that the works at Rath Lugh are being done according to "best practice", and are not damaging the national monument.
He described it as one of the greatest shameful acts of cultural vandalism that took place in any part of Europe.
Professor Eogan has agreed to give an affidavit for a High Court case being taken by Gordon Lucas seeking an injunction on the works in the Tara complex.
The action was filed on 5th. February, and is awaiting a hearing date.
Also on Thursday last, in a major Garda operation at Rath Lugh, a number of arrests were made at the protester's camp and the defendants appeared in Navan District Court on Thursday evening.