Authorities in British Columbia arrested anti-pipeline protesters Saturday on Burnaby Mountain, a first in a string of actions demonstrators said they have planned for the coming week.

Amina Moustaqim-Barrette, who spoke on behalf of a coalition of demonstrators under the banner Protect the Inlet, said each protester was ready to be arrested to send a clear message against Kinder Morgan's Trans Mountain pipeline expansion project.

"The community isn't going to lay down and just accept that this pipeline is going to be built," she said. "They're going to show their opposition very loudly and very purposefully."

Twenty-eight demonstrators began blocking the entrance to Kinder Morgan's work site at about 10 a.m. PT Saturday. Four hours later, some of the protesters tied themselves to the gate using zip ties, Moustaqim-Barrette said.

Burnaby RCMP moved in soon after, reading out a B.C. Supreme Court injunction granted Thursday to Kinder Morgan, she said. The injunction restricts protesters from entering within five metres of two terminal work sites.

Moustaqim-Barrette said all 28 demonstrators had been arrested by Saturday evening after what she described as a "very peaceful" demonstration.

"Everyone was very aware of the situation, of the possibility of arrest. And everyone was given the chance at any time during the day to leave that zone and not be arrested," said Moustaqim-Barrette, who is also communications co-ordinator for environmental organization 350.org.

She said there are similar actions planned for each day starting Monday, which will involve Indigenous leaders, politicians, celebrities and grassroots volunteers.

Officials with Burnaby RCMP were not available for comment Saturday, but the police service said Friday they wanted to remind the public that they are not an interested party in the pipeline debate and are there to ensure everyone's safety.

Canada's natural resources minister Jim Carr said Thursday that Ottawa is determined to see the Trans Mountain pipeline expanded, despite an interprovincial dispute on whether the project should go ahead.

Jason Kenney, leader of Alberta's United Conservative Party opposition party, weighed in on Saturday's protest via Twitter.

"They have a right to protest, but should not be allowed to block access to the worksites. The rule of law must be upheld," Kenney said. "Radical activists cannot be allowed to delay the approved Trans Mountain pipeline to death."

Alberta and B.C. have been locked in a battle over the future of Kinder Morgan Canada's $7.4-billion plan to triple capacity of the Trans Mountain pipeline, which runs from Edmonton to Burnaby.