The multibillion-dollar project to build Canada’s first liquefied natural gas export plant is facing opposition from indigenous people who live on the planned route of the pipeline to supply the facility. The LNG Canada project, led by Royal Dutch Shell, plans to transport gas from the Montney shale field in northern British Columbia to markets around the world. With a total cost estimated at about $30bn, it is the largest private sector investment in Canada’s history, and central to the government’s strategy of increasing energy exports.

The other partners in the project are Petronas of Malaysia, PetroChina, Kogas of South Korea and Mitsubishi of Japan, and the plant’s site at Kitimat on British Columbia’s coast means it is well located to serve Asian markets. Justin Trudeau, Canada’s prime minister, said last week that the gas from the plant would “supplant coal in Asia as a power source and do much for the environment”. However, some members of a First Nations community have objected to the construction of the 420-mile pipeline between the gasfield and the LNG plant, saying it threatens salmon spawning grounds. People from the Wet’suwet’en nation set up two roadblocks on their land, to keep out workers from the pipeline company Coastal GasLink, a subsidiary of TransCanada.

The broke up one of those roadblocks on Monday, making 14 arrests, and on Wednesday reached an agreement to open the other, but some hereditary chiefs of the Wet’suwet’en said they remained opposed to the pipeline, and the project faces legal challenges and potentially further obstruction. Coastal GasLink aims to have the pipeline in service by 2023, in time to support the planned start-up of the LNG Canada export plant “by the middle of the next decade”, with peak construction activity under way in 2020-21. Jennifer Wickham, a spokesman for the group of Wet’suwet’en people fighting the pipeline, said the hereditary chiefs had responsibilities handed down for thousands of years.

“When people take on a chief’s name, they accept the responsibility to care for the lives in the territory, and that includes the people, animals and salmon,” she said. Coastal GasLink has secured environmental approvals from regulators in British Columbia, which cover expected impacts on salmon and other wildlife, but opponents of the pipeline say they believe the potential disruption to spawning grounds is unacceptable.