Protesters trying to prevent workers employed by Shell contractors from getting on to the 400-acre site of the proposed Corrib gas terminal in north Mayo staged a flying picket on a road a mile away.
Instead of picketing the main entrance to the site at Bellanaboy shortly after dawn yesterday, the protesters chose a location on the Bangor Erris to Bellanaboy road to stage a sit-down demonstration.
Some 100 demonstrators sat down on the road for about three hours from daybreak.
They blocked the roadway and later delayed the passage of workmen in jeeps, vans and lorries containing building materials trying to gain access to the site for about 25 minutes, until they were moved by gardaí.
Gardaí brought in reinforcements to reopen the road and ensure safe passage for the workers.
Although there were no arrests and nobody was injured, Supt Joseph Gannon, officer in charge of the Belmullet Garda district, expressed concern afterwards about the tactics and "new level of aggression" shown by the protesters.
"Their actions were in breach of a verbal undertaking given us on Thursday evening last through Independent TD Dr Jerry Cowley that the protests would be peaceful and lawful."
Supt Gannon referred to what he described as "an upsurge in preparedness" by the protesters and said some of them had flailed out with their feet while sitting on the roadway in order to make it more difficult for gardaí to remove them.
Just over 100 gardaí remain on security duties at Bellanaboy but Supt Gannon pledged there would be an immediate reduction in numbers if he got an undertaking that there would be no further attempts at obstruction.
Christy Loftus, Shell's external affairs adviser, said: "Obviously the continuing attempts at blockades are of concern to us.
"We would prefer to be able to carry out essential maintenance work on the site without impediment.
"We have no problems with people protesting provided the right of workers to get on to the site is not interfered with."