A scaled down operation is continuing at the site of the Corrib gas terminal in Co Mayo tonight.
A small force of gardaí were on duty at the entrance to the site as construction workers left the complex.
Earlier today 170 gardaí had escorted the construction teams onto the site and had removed 100 members of the shell to sea campaign on the main entrance.
Members of the Shell to Sea protest group jeered loudly this morning as cars containing the workers drove onto the Bellanaboy site, followed by a number of trucks.
Vincent McGrath, who spent 94 days in prison last year for contempt of court arising from proceedings over the development, said that the show of force by gardaí would only serve to strengthen the resolve of those people who were opposed to the terminal.
Members of the Shell to Sea campaign are opposed to the location of the terminal on health and safety grounds.
Last week the contract workers were prevented from entering the site of the planned €200m onshore facility.
In a separate development tonight, members of the shell to sea group in Galway have mounted a picket on the Garda headquarters there at Mill Street.
They say they are demonstrating against the level on Garda activity involved in the operation at the gas terminal site at Bellenaboy during the day.
Shell Ireland said its pleased that it has been able to resume work on the site and will now continue with preparatory work for the building next year of the 200 million euro gas treatment plant.