An Indigenous group is urging other First Nations to not invest in the Trans Mountain pipeline expansion, arguing it is not a sound investment.

The Union of B.C. Indian Chiefs (UBCIC) has penned an open letter to some leaders who are exploring the idea of partial ownership in the project.

It warns of potential financial risks tied to the proposed pipeline expansion if it gets the ultimate green light from Ottawa.

"The bottom line is that there is no certainty in this investment," said Judy Wilson, secretary treasurer with the UBCIC. She co-signed the letter with Grand Chief Stewart Phillip.

"A lot of the communities may not have the full financial information and a lot of things they should know if they are going to be investing."

Chief Judy Wilson with the Union of B.C. Indian Chiefs says that she chooses the health of the southern resident killer whales over the Trans Mountain pipeline expansion. (Chantelle Bellrichard/CBC)

The letter outlines concerns around ballooning constructions costs of the project, citing total cost estimates upwards of $15 billion.

"When people start doing the actual number crunching they'll see there's no real return," said Wilson, referencing last year's buy-out by the federal government.

In May 2018, the LIberal government announced it would buy the Trans Mountain pipeline and related infrastructure for $4.5-billion from Kinder Morgan after it came under opposition from environmentalists, Indigenous groups and the B.C. government.

The proposed expansion would triple the flow of oil products carried in the 980-kilometre pipeline, which runs from Edmonton to Burnaby.

"Kinder Morgan did the math and saw there was no real project for them so they didn't want to take all that risk," Wilson said.

She called it a 'stranded asset', pointing out many communities are still adamantly opposed to the project and plan to continue fighting it.

"There are other ways to invest but we have to be able to be willing to do that in partnership...I think there are a lot more willing partners that are interested in protecting the environment."

'It's a real opportunity'

However, the Indian Resources Council of Canada, which advocates for First Nations energy development, insists the letter won't stop it from supporting project.

"I can proudly say that our members are experts in oil and gas, and we can recognize a good investment," said president and CEO Stephen Buffalo.

Buffalo said he respects the opinions of Indigenous leaders opposed to pipelines, but believes many communities would still stand to benefit from the Trans Mountain expansion.

"It's a real opportunity for First Nations to be a part of something," he said. "This is just one way and, of course, we have to do things right."

Buffalo, who's based in Calgary, said his group represents more than 130 oil-and-gas-producing First Nations across Canada.

"The debate is extremely polarized," said Stephen Buffalo with the Indian Resource Council, which is considering investing in the Trans Mountain pipeline project. (CBC)

"We've become gold medalists in managing poverty under the Indian Act. We want to change that. We want to be gold medalists in managing wealth."

Buffalo acknowledged the UBCIC letter did make some good points, but he wants to double-check some of the claims.

"They make some fair arguments, but some of them are very speculative," he said. "It won't really defer me from trying to pursue what we're intending to do."

He added he's looking to meet with the federal government to start discussions about possible investment opportunities if Ottawa approves the project.

Natural Resources Minister Amarjeet Sohi admitted this week there's no guarantee a final decision on the project will be made before the fall federal election.