B.C. is looking to join the legal fight against the Trans Mountain pipeline expansion project.

Nearly two dozen conservationist groups and some First Nations are challenging the federal government's approval of the project.

On Thursday, B.C. Environment Minister George Heyman and Attorney General David Eby said the province would be seeking intervener status on the legal action.

That status would allow the province to formally back the challenge, even though it wasn't named in initial filings.

Heyman announced the province had hired lawyer Thomas Berger, a former B.C. Supreme Court justice, to provide advice to the government in its next steps.

Ecojustice lawyers, on behalf of the Living Oceans Society and Raincoast Conservation, said Ottawa broke the law when it relied on a National Energy Board assessment of the Kinder Morgan project.

The groups argue the board — and thus the Liberal government — didn't properly account for the pipeline's environmental impact before approving the expansion.

Envmt Min. George Heyman announces province has hired outside counsel to begin legal challenge of Kinder Morgan expansion pipeline <a href="https://twitter.com/hashtag/bcpoli?src=hash">#bcpoli</a> <a href="https://t.co/3jEJ3TheLp">pic.twitter.com/3jEJ3TheLp</a> —@FarrahMerali

Several First Nations are also taking action, saying they weren't properly consulted before the federal go-ahead.

The groups are asking the courts to overturn the decision.

NDP election promise

"Mr. Berger will provide legal advice to government on the options for participation in legal challenges," the environment minister said.

Both Eby and Heyman campaigned against the $7.4-billion project during the spring election.

Halting the expansion was also a key campaign promise for Premier John Horgan, who has said he'll use "every tool in the toolbox'' to stop the project.

In July, Eby said the NDP government had already ruled out delaying permits as one way of blocking construction. He said doing so would put the province at risk for a costly lawsuit from Trans Mountain, a subsidiary of Kinder Morgan Canada.

The proposed pipeline would triple the 1,150-kilometre pipeline's capacity to move oil between Edmonton and Burnaby, B.C.

Kinder Morgan's Trans Mountain expansion project's Westeridge loading dock is seen in Burnaby, B.C., in November 2016. (Jonathan Hayward/Canadian Press)

Eby and Heyman also said the government would be reviewing how it consults with First Nations in regard to the environment as part of Thursday's announcement.

In response, B.C. Opposition leader Rich Coleman said British Columbians should be "concerned" about the province's move.

"The B.C. NDP have unilaterally declared the First Nations consultations are incomplete, even though the federal government has said the consultation was appropriate before they approved the project," Coleman said.

Kinder Morgan calls scrutiny 'unprecedented'

In a statement, Kinder Morgan Canada president Ian Anderson said the company would review the government's announcement and work to meet its concerns.

"We are committed to working with the province and permitting authorities in our ongoing process of seeking and obtaining necessary permits and permissions," Anderson said.

"We have undertaken thorough, extensive and meaningful consultations with Aboriginal Peoples, communities and individuals and remain dedicated to those efforts and relationships as we move forward with construction activities in September."

The company's statement noted the project was approved by the National Energy Board and the federal government after "unprecedented" scrutiny and said the project would bring jobs and economic benefits.

September construction 'highly unlikely': minister

Appeal hearings for the federal challenges are set for November, two months after construction on the pipeline is scheduled to begin.

However, Heyman said only three of eight environmental management plans that would allow work to begin have been accepted. He said it's not likely that the other five will be completed before the fall.

The plans haven't been accepted so far because the company didn't adequately consult First Nations, the minister said.

In the meantime, the ministers said Berger will also be asked to flag the government about any other legal tools available to stop the project.