Two federal politicians, including Green Party Leader Elizabeth May, have been arrested at a protest against Kinder Morgan's Trans Mountain pipeline expansion in Burnaby, B.C.

May and NDP MP Kennedy Stewart joined demonstrations on Friday, opposing construction of the federally approved Trans Mountain expansion.

May, the MP for Saanich–Gulf Islands, stood in line with activists at the gate of a Kinder Morgan worksite. She was arrested around noon PT and released within half an hour.

She said she's been charged with civil contempt for blocking the road. It is not a criminal offence.

"I have never before put my signature on a line that said 'signature of accused,' but my rights have been read to me and I will return to court on June 14," she told reporters after her release.

May said she is free to "continue to protest, continue to oppose Kinder Morgan's erroneous permit."

.<a href="https://twitter.com/ElizabethMay?ref_src=twsrc%5Etfw">@ElizabethMay</a> has been released. <a href="https://t.co/0bgBTiwbaK">pic.twitter.com/0bgBTiwbaK</a> —@raffertybaker

Stewart, who represents the federal riding of Burnaby South, also entered a court-imposed protest-free zone around the property. He was arrested around 12:30 p.m. PT and released shortly afterwards.

"This is down to Justin Trudeau's broken promises," he said as he walked with RCMP officers.

.<a href="https://twitter.com/kennedystewart?ref_src=twsrc%5Etfw">@kennedystewart</a> has been arrested. <a href="https://t.co/lyK1vaBW9r">pic.twitter.com/lyK1vaBW9r</a> —@raffertybaker

A statement from protest organizers says nearly 100 people have already been taken into custody for violating the court order.

The injunction prohibits activists from getting within five metres of Kinder Morgan's two terminal sites on Burnaby Mountain, where work related to the company's pipeline expansion is underway.

In a written statement, May said she respects the courts and does not take the injunction lightly but believes the pipeline project will cause irreparable harm to the environment and Indigenous rights.

May marched with anti-pipeline activists during a rally in Burnaby earlier this month.

NDP MP Kennedy Stewart was also arrested at Friday's protest in Burnaby, B.C. (Rafferty Baker/CBC)

Protest organizers have said they're planning daily demonstrations until at least Monday, the deadline given to Kinder Morgan for clearing trees in the area before birds begin nesting.

Dozens of protesters have been arrested for violating the court order this week, including 19 on Monday.

More activists blocked the entrance to the Kinder Morgan offices in downtown Calgary on Friday to protest the expansion project.

May, centre, and Stewart, left, lined up with other protesters against a gate at a Trans Mountain worksite — violating a court-ordered injunction to stay away from the company properties. (Rafferty Baker/CBC)

With files from the Canadian Press, Rafferty Baker and Anita Bathe