CALGARY -- The B.C. government has launched its latest effort to hinder development of Kinder Morgan Inc.'s Trans Mountain expansion project with a proposal to at least temporarily restrict increases in diluted bitumen shipments.

Environment Minister George Heyman said Tuesday that the province plans to ban the increase of oil exports until it can determine through an advisory panel that shippers are prepared and able to properly clean up a spill.

"Our proposal is to restrict the increase of (diluted bitumen) through regulation until we can be certain there are appropriate measures to prevent a spill, and to adequately clean it up to prevent catastrophic damage if it happens on any number of fronts," he said.

"If we can't be satisfied that that can happen once we receive the scientific advisory panel, there would be no reason to lift the restriction."

The government will establish an independent scientific advisory panel to study the issue, and will also seek input from First Nations, industry, local governments, environmental groups and the general public over the coming months, said Heyman.

The proposal creates more uncertainty for Kinder Morgan's (KMI.N) already-delayed Trans Mountain expansion project that would nearly triple the capacity of its pipeline system to 890,000 barrels a day.

The company said it would actively participate in the engagement and feedback process that the province has announced, while pointing out that the Trans Mountain expansion project was already thoroughly studied before it secured approval.

"The expansion project's approval by the Government of Canada followed a rigorous and lengthy regulatory process that included a thorough examination of the pipeline and products being shipped."

B.C.'s move was met with condemnation by Alberta Premier Rachel Notley, who has long championed the pipeline to get Alberta crude to new markets.

"Having run out of tools in the toolbox, the government of B.C. is now grasping at straws," said Notley, calling the proposal rash, illegal and unconstitutional.

"It is so far beyond the scope of what they have the legal ability to do, they are creating a mockery of our federal system, and it truly does jeopardize investor confidence," said Notley.

Opponents of the project in B.C. -- including numerous environmental groups -- welcomed the move.

West Coast Environmental Law executive director Jessica Clogg said it was a clear threat to the project.

"What this really is, is an enormous sword hanging over Kinder Morgan," said Clogg.

"It's a wake up call of what's coming, and really I think has to be taken very seriously, because it's a signal that if the science is not there to show that a spill can be cleaned up safely and effectively, Kinder Morgan may not be in a position to turn on the tap, even if they can get their project built."

Environmentalists have been waiting for an announcement like this for a while, said Clogg, after the B.C. NDP committed along with the B.C. Green Party to oppose the pipeline with all available tools.

B.C. Green Party Leader Andrew Weaver said in a release that he was pleased to see the minister is putting evidence and science front and centre in government decision-making.

"I look forward to the new panel providing complete, robust and accurate information on this matter to the Minister that reinforces what which we already know - that there is no way currently to adequately respond to a spill of diluted bitumen."