Photo: The Canadian Press. All rights reserved.

RCMP officers take protesters into custody at an anti-pipeline demonstration in Burnaby, B.C., on Thursday, Nov. 20, 2014. THE CANADIAN PRESS/Jonathan Hayward

A judge raised serious doubts Thursday about charges laid against dozens of anti-pipeline activists on a mountain near Vancouver, the same day a prominent First Nations leader was arrested at the site.

Grand Chief Stewart Phillip of the Union of BC Indian Chiefs crossed a police line on Burnaby Mountain, where Kinder Morgan is conducting drilling and survey work related to the proposed expansion of its Trans Mountain pipeline.

While that was unfolding, a lawyer for the company was in a Vancouver courtroom asking a judge to expand an injunction that has been used to arrest more than 100 people, including Phillip. Nearly all of them have been charged with civil contempt for violating the order.

A company lawyer said the GPS co-ordinates used in the initial injunction application — and, subsequently, in the court order — were inaccurate. The company wants the co-ordinates updated and the injunction's timeline extended.

BC Supreme Court Judge Austin Cullen suggested the error could put the civil contempt charges in jeopardy.

A hearing related to the protesters' contempt charges has been scheduled for Jan. 12. Cullen suggested that may be too long to wait if the charges are in doubt, but it wasn't clear if he planned to take action sooner.

Like many pipeline opponents before him, Chief Phillip announced his intention to be arrested before walking past a police line that surrounded the work site.

Phillip and his supporters trekked through dense brush to the work site. He was arrested to the beat of a native drum and singing.

"I said that if push came to shove and there were arrests, that I would stand with the courageous people that were willing to be arrested as a matter of principle," he said before his arrest.

"We need to reclaim this country ... and return it back to the voices of the people that have invested a lifetime of hard work to build this province."