NEW HAVEN, PRINCE EDWARD ISLAND -- Police are defending the arrests of Green party protesters at the site of a highway realignment in Prince Edward Island, saying they acted to ensure the safety of those in a construction zone.

On Tuesday, the interim leader of the provincial Green party, Darcie Lanthier, said she was arrested and carried off the construction site as crews cut down trees in the Bonshaw Hills.

Earlier in the day, the RCMP said five people were asked to leave the site and then served with tickets for trespassing.

Peter Bevan-Baker, the incoming leader of the provincial Green party, says he was among those charged with the summary offence.

Federal Green Leader Elizabeth May criticized the RCMP's actions in a news release on Wednesday.

"He (Bevan-Baker) was on public land. There is a constitutional right to assemble peacefully," May said in the release.

"These trespassing charges are unreasonable and I demand they be dropped immediately by the RCMP."

RCMP Sgt. Andrew Blackadar says the courts will decide if charges are justified and police have to ensure the construction site remains safe.

"Certainly people do have the right to lawful assembly and they can protest the construction," he said.

"However, this is a working construction zone and there has to be safety parameters put in place ... to ensure it is a safe work site. That's the reason the trespassing tickets were issued."

May likened the actions of the protesters to the non-violent civil disobedience of Nobel Prize winner Wangari Maathai, famed for defending forests in Kenya.

She urged Islanders to join the provincial party "in this important ecological struggle."

Alyssa MacAusland, a protester who has spent time at the camp, says members of the group are willing to risk being taken into custody to stop the project to build a six-kilometre section of the Trans-Canada Highway.

The 25-year-old estimates about 30 people are in the area, but she says if the RCMP order the campers to leave then a smaller group will remain to oppose the cutting of trees in the area.

Opponents of the project say the $16-million road will cut through an old-growth hemlock forest and force unnecessary expropriation of private land.

The province says that the existing route has too many sharp bends and dangerous hills, and needs to be replaced.

Blackadar says he had no further reports of protesters being arrested or fined.

"Work is closing there for the day and our members haven't really been on the site," he said.

"The RCMP won't be back on the site unless they get a call by either the contractor or people there protesting."

Bevan-Baker, who becomes leader of P.E.I.'s Greens in November, said the disobedience is necessary to slow the project down.

"We felt all along this would be the end game, that it would end up with people tying themselves to trees in the old-growth Acadian forest, which is exactly what has happened," he said in an interview Wednesday.