Members of a B.C. First Nation are launching another legal challenge of a massive liquefied natural gas project proposed for the province's north coast.

Several hereditary chiefs with the Gitxsan First Nation are in Vancouver today to announce their opposition to the Pacific Northwest LNG project, a project backed by Malaysia's state oil company Petronas.

The group's traditional territory is in northwestern B.C., where the proposed $11.4-billion LNG export terminal would be built close to Prince Rupert, B.C.

The chiefs say the project will be harmful to fish in the Skeena River and infringes on the First Nation's fishing rights.

"The Canadian government's decision to approve this project did not respect our fishing rights protected under the Canadian Constitution," said Gitxsan Hereditary Chief Yvonne Lattie in a statement. "We were not consulted."

The federal government announced its approval of the $36-billion terminal and pipeline project in September, subject to 190 conditions, including a cap on carbon emissions.

The Gitxsan challenge is in addition to other actions by area First Nations that are asking the Federal Court for a judicial review of the approval, alleging the government failed to properly consult with them.

Pacific NorthWest LNG has said it has been meeting with local First Nations since 2012 and is continuing to work with them.