A B.C. First Nation group has reversed its support for the Enbridge Northern Gateway pipeline project, but the company says it still has the support of almost half the bands along the corridor.

Gitxsan Treaty Society negotiator Elmer Derrik signed the agreement last month, but 36 Gitxsan hereditary chiefs voted to officially reject it during a meeting Tuesday night.

The agreement Derrick struck would have given the First Nation a $7 million equity stake in the project, but it set off a storm of protest among other Gitxsan members who then staged a blockade of the Treaty Society office in Hazelton.

Gitxsan spokesman John Olson said the chiefs may be prepared to lift their blockade, but that would be decided in another meeting.

The chiefs also said they want written acknowledgment from the Gitxsan Treaty Society that the Enbridge deal is rejected before removing the protest.

Paul Stanway, a spokesman for Enbridge on the Northern Gateway pipeline project, said the company is disappointed in the shift, but that Enbridge hasn't given up on reaching a deal with the Gitxsan.

"We understand the concerns that have been raised and our goal here is to reach a long-lasting agreement with the Gitxsan so they can be equity partners in the ownership of Northern Gateway."

Enbridge representatives were allowed to attend Tuesday's meeting, he said.

"The feeling was they wanted to take a fresh look at this deal and we respect that."

Larry Patsey, a hereditary chief, said he didn't attend the meeting because he doesn't recognize the treaty society.

"As far as we're concerned all that business is null and void," he said. "Certainly, we're happy to hear that the chiefs that were there spoke against Enbridge and the deal was nullified."

Patsey said 48 hereditary chiefs signed a Dec. 5 declaration against Enbridge and the treaty society because they felt the society wasn't representing them and they felt left out of the process.

The Gitxsan have 65 houses, he added, each of which is represented by a hereditary chief. He said each of the houses must be consulted.

"Hereditary chiefs are always open to economic development endeavours in our territory, but we have to be consulted and accommodated in all these aspects of negotiations," he said.

The collapse of the only public support from an aboriginal group is unwelcome news for Enbridge.

British Columbia is blanketed virtually entirely by a complicated quilt of overlapping land claims and securing the support of aboriginal groups along the line would allow Enbridge to avoid costly and lengthy legal battles to make the pipeline a reality.

The news also comes on the same day as President Barack Obama rejected plans for the high-profile Keystone XL pipeline through the heart of the United States. That pipeline, proposed by TransCanada Corp., was the subject of a high-profile activist campaign that drew Hollywood stars into the fray to oppose it.

Stanway said Enbridge has managed to get the support of 20 aboriginal groups among the 45 within 80 kilometres of the pipeline corridor in recent weeks. They have signed equity agreements with the company.

"We're confident that's good momentum from our point of view. The deal is open until the end of May 2012."

Stanway wouldn't name the First Nations who have signed deals.

Dozens of B.C. First Nations are opposed to the pipeline and have expressed their concerns at public hearings being held in Northern B.C.

The twin pipeline project between Alberta and northwest B.C. will allow Alberta oil to be loaded onto tankers on the West Coast.

Derrick told The Canadian Press in an earlier interview that he felt the agreement would bring employment opportunities to First Nations communities.