Canada's Environment Minister is defending the federal cabinet's approval of a major project to export liquefied natural gas from British Columbia after two First Nations and a fishing conservation group launched lawsuits Thursday in a bid to block the proposal.

"The government of Canada stands behind its decision on the Pacific NorthWest LNG project," Catherine McKenna said in a statement issued Thursday by her department and the Canadian Environmental Assessment Agency. "This project underwent a three-year rigorous and thorough science-based process that evaluated and incorporated mitigation measures that will minimize the environmental impacts."

But the Gitwilgyoots tribe of the Lax Kw'alaams First Nation, the Gitanyow hereditary chiefs and the SkeenaWild Conservation Trust are opposed to the plan to build an $11.4-billion export terminal near Prince Rupert.

Story continues below advertisement

Related (for subscribers): Approval of B.C. LNG project keeps Trudeau's grand bargain together

Related: B.C. government promises millions in benefits for LNG support

Read more: Seven things to know about the Pacific NorthWest LNG project

The Gitwilgyoots, Gitanyow and SkeenaWild filed separate applications pushing for a judicial review in federal court. The three legal applications are seeking a court order that would quash the federal cabinet's approval of Pacific NorthWest LNG, which is led by Malaysia's state-owned Petronas.

Respondents named in the three court applications are the federal cabinet, the federal Environment Minister, the CEAA and Pacific NorthWest LNG. The cabinet approved the project last month, subject to more than 190 conditions, including a cap on greenhouse gas emissions of almost 20 per cent below what was first proposed.

Locally, the key concern is the threat to Flora Bank, a sandbar located next to the proposed export terminal site on Lelu Island. Chris Tollefson, one of the lawyers representing SkeenaWild, said the CEAA did not properly assess and report on how the terminal would affect juvenile salmon habitat on Flora Bank.

"This is really the cradle for the salmon. When you alter or destroy the habitat, you really don't know what is going to happen," Mr. Tollefson said in an interview.

Story continues below advertisement

The CEAA has ruled that the LNG proposal would likely harm harbour porpoises and contribute to climate change, but the agency sees low ecological risks to salmon as long as mitigation measures and monitoring programs are carried out.

Greg Knox, SkeenaWild's executive director, described the CEAA's review process as flawed. "Putting in a massive bridge and piling structures the size of the Golden Gate Bridge right over top of this critical habitat could be devastating for this whole watershed," he said.

Pacific NorthWest LNG issued a release defending its project, which includes building a suspension bridge and a trestle-supported pier from Lelu Island to a planned dock on Agnew Bank for LNG carriers.

"We are continuing to work collaboratively with area First Nations as we move through the various stages of the project," said Tessa Gill, head of external affairs.

Pacific NorthWest LNG has pointed out that it has consulted with five Tsimshian First Nations – the Metlakatla, Kitselas, Gitxaala, Kitsumkalum and Lax Kw'alaams. Four of those have signed term sheets intended to lead to impact benefit agreements, but the Lax Kw'alaams First Nation is obviously the holdout.

One of the key critics of Pacific NorthWest LNG has been Donnie Wesley, a Gitwilgyoots hereditary chief who helped start a protest camp on Lelu Island in August, 2015. Mr. Wesley and his supporters say no amount of mitigation measures would protect Flora Bank in the Skeena River estuary.

Story continues below advertisement

Complicating matters, Lax Kw'alaams Mayor John Helin has said his elected band council is open to potentially supporting the proponents of LNG exports from Lelu Island. "It's a saga. It's a long soap opera story," said Mr. Wesley, who is also known as hereditary chief Yahaan.

The Gitwilgyoots tribe is one of nine allied tribes of the Lax Kw'alaams First Nation, which claims Flora Bank and Lelu Island as part of its traditional territory.

The Gitanyow's traditional territory is roughly 150 kilometres northeast of Flora Bank, and Gitanyow leaders say their concerns have been largely ignored because their territory is farther away. Glen Williams, the chief negotiator for the Gitanyow hereditary chiefs, says the federal government has failed to properly consult with his group.

With liquefied natural gas prices in Asia at low levels, the vast majority of the 20 LNG proposals in British Columbia have been rendered unviable.