A Greenpeace protest at Kinder Morgan's Trans Mountain Pipeline terminal in Burnaby, B.C., is over, after activists voluntarily left the site at around 6:45 p.m. PT Wednesday night.

The group is protesting the proposed expansion of the pipeline, which would triple its capacity to carry crude oil from the Alberta oilsands to tankers in Vancouver.

Greenpeace spokesperson Peter Louwe said their protest action began at 7 a.m. PT Wednesday and that two protesters had climbed onto the oil pumping mechanism.

Fourteen others were also on the scene, chained to fences or strapped to pipelines.

Greenpeace protesters at Kinder Morgan

Tsleil-Waututh elder Amy George "Halth-Leah" was at the Kinder Morgan facility to support Greenpeace. (CBC)

They were joined by at least one elder of the Tsleil-Waututh First Nation, whose traditional territories span across the shores of the Burrard Inlet and who are now based on the shore opposite Kinder Morgan's shipping facility.

The Greenpeace action comes only days after the Tsleil-Waututh held their own protest, sailing across the Burrard Inlet in traditional canoes.

Rex Weyler, the co-founder of Greenpeace International, also took part in the protest on Wednesday.

"This is the biggest risk to the British Columbia coast that I can remember," said Weyler.

"We want to avoid a major oil spill on the coast of British Columbia. We don't want to be the tarsands shipping port."

Kinder Morgan spokesperson Andrew Galamyk told CBC News in a statement that no ships were scheduled to arrive at the terminal Wednesday, so the protest actions were having a minimal impact on their operations.

"Our focus today is the safety of our staff, the facilities, the protesters and the community. We respect the rights of protesters to advance their cause, but in this case we are very concerned about this trespass and disturbance," said Galamyk .

The Kinder Morgan facility is the west coast terminus of the Trans Mountain pipeline, which carries Alberta bitumen from the Edmonton area, across southern British Columbia to port just east of Vancouver in Burrard Inlet, for shipment overseas.

When completed, the proposed expansion is expected to increase capacity in the Trans Mountain pipeline from the existing capacity of 300,000 barrels per day to 850,000 barrels per day.

Mike Hudema, a climate and energy campaigner for Greenpeace Canada, said the group came to make a point.

"We came to... draw attention to the tarsands and the threat they pose," said Hudema.

"Over 130 B.C. First Nations and the majority of British Columbians have said no to tarsands pipelines and tankers, and we need that message to be delivered across the country and to Harper.

"This was an important step in helping us achieve our goal."

Several RCMP officers attended the scene, but no action was taken and no arrests were made.

Once protesters began to leave the site, those from outside Metro Vancouver were escorted by police for processing.

Others were free to return home after providing their details. The Crown will decide whether any charges should be laid in the coming days.

With files from The Canadian Press