Opponents of the plan to build the new M3 motorway alongside the Hill of Tara are to protest outside the Green Party's national meeting in Dublin today.
Green supporters from across the country are gathering to decide whether to ratify plans for the party to go into coalition with Fianna Fáil and the PDs.
Members of the TaraWatch campaign have described the coalition deal as a sell-out of Green Party principles and policies, even though details have not been made public.
The Greens have previously called for the M3 to be rerouted away from the Hill of Tara and TaraWatch says any deal that does not include a reassessment of the motorway spells political suicide for the party.