Protesters will today picket a Dublin seminar attended by the National Roads Authority over plans to build a motorway past the Hill of Tara.
The demonstration will be led by the Save Tara Skryne Valley Group and Tara Watch, which are both opposed to the new M3 passing near the ancient site in Co Meath.
The M3 protest groups are mounting their demo as part of the Climate Change Challenge series of protests. Thousands of daily commuters have blamed the delay in building the motorway for congestion around Co Meath towns.
The event in Ballsbridge will hear a presentation on the "Delivering the National Roads Network - Value for Money?" by NRA chief Fred Barry.
Issues discussed will include a cost/benefit analysis on the national roads network and comparisons between Irish and other European countries.