Gardaí this morning escorted a small group of people believed to be part of the Shell to Sea campaign from the Corrib gas refinery in north Mayo.
A Garda spokesperson told ireland.combetween 20 and 30 people were removed peacefully from the site, having returned there after a protest was carried out by hundreds of Shell to Sea campaigners this morning.
Around 600 protesters from across the country arrived at the Bellanaboy refinery at 7am for a mile-and-a-half walk to the refinery from the nearby Glenamoy bridge.
Campaign organisers said they had planned a peaceful protest with a carnival atmosphere for the protesters - who came from Dublin, Cork, Belfast and Ennis - to show their support for the local community in the dispute with the Shell Oil company over its proposed onshore pipeline.
Mary Corduff of Shell to Sea told ireland.comthe protest went off peacefully and that campaigners were moving to a local pub for refreshments at around 9.30am when news came that a number of people had entered and occupied the refinery site.
Ms Corduff said she didn't know if the people who entered the plant were members of Shell to Sea, but insisted their campaign went off peacefully as planned.
"I don't know who did it or what the purpose was," she said. "We had nothing to do with it".
The Shell to Sea campaign, which holds regular public meetings, has been dogged by a reputation for confrontation since violence broke out at a November 10th rally outside the Corrib plant where eight people, including four gardaí, were injured.
Mark Garavan of Shell to Sea said: "We were very anxious to ensure that wouldn't happen. It was not part of our planned day at all. But it seems some people were determined to make that happen."
One of the protesters removed from the gas refinery this morning, Ms Maura Harrington, told ireland.comthere were 150 protesters on site at the Corrib plant who went there to see for themselves what safeguards are in place to protect their local water supply, Carrowmore lake.
"We weren't being told anything," she said. "We feel abandoned by the statutory body supposed to be working on our behalf".
Last month the Environmental Protection Agency said it was satisfied that emissions from the refinery would not adversely affect human health or the environment and would meet all the relevant national and EU standards.