Aboriginals fearing a spill are threatening to try again to block Canada's first pipeline connecting the rich oil fields of Alberta to the Pacific Coast aiming to reach new markets in Asia.

Pipeline giant Enbridge has hinted in recent months it would soon receive a nod from the federal government to finally start construction of its Northern Gateway project, which has been postponed several times in the past decade due to financial setbacks and environmental concerns of regulators.

The project would see up to 525,000 barrels of crude oil from Alberta's oil sands piped 1,125 kilometers (700 miles) daily through the Rocky Mountains to an ocean terminal in Kitimat, British Columbia.

Coastal residents fear an eventual spill will devastate the pristine maritime environment of British Columbia's north coast, its temperate rain forests and abundance of marine life, and despite Enbridge's environmental safety assurances are vowing to fight it.

Canada has the third largest oil reserves in the world, much of it in the black, gooey sands of northern Alberta's Athabasca region.

Its main energy customers are in the central and eastern United States at present, where older pipelines connect.

Enbridge estimates that by opening up new markets overseas and along the US Pacific Coast the new pipeline could rake in an additional CAN$28 billion (US$28.4 billion) for Alberta oil producers in its first decade of operation.

But for those that lie in its path, that's not incentive enough.

The project will cut a line straight through several aboriginal communities, which fear someday that black oil could gush into coastal waters and sensitive forests, affecting humpback whales, orca pods, and rare white-haired Kermode grizzly bears.

"There is nothing that they can offer that will replace the culture we already have and this tanker traffic jeopardizes our culture," said Art Sterritt, chief of the Coastal First Nations.

"There is no amount of money that could compensate us for losing our heritage and our culture."

Enbridge has offered cash to the communities, but was rebuffed.

Millions of dollars from coastal salmon, halibut and cod fisheries and fish farms and eco-tourism -- including bear watching in Great Bear Rainforest and whale watching tours -- are also at risk from oil shipping, the pipeline's detractors said.

Enbridge, which declined to comment for this story, also pledged to bolster safety measures, following spills last year in the United States.

These include double-hulled tankers, local guides to help ships navigate the coastal waters and emergency spill response stations.

"The only way that Coastal First Nations would ever reconsider this project is if Enbridge could assure Coastal First Nations there would never be a tanker accident," Sterritt said.

But even with the most advanced safety systems in place, no oil company can guarantee this, he added.