VANCOUVER -- Jason Kenney, Alberta's Opposition leader and candidate for premier, says his government would ensure "serious consequences" for British Columbia if it blocks the Trans Mountain pipeline expansion.

Kenney said Monday he would be prepared to stop permits for the shipment of Alberta oil to B.C. through the existing Trans Mountain line, which pumps 300,000 barrels a day of oil, gasoline and other petroleum products to Metro Vancouver.

"If British Columbia is unwilling to help us export Canadian energy, then I would ask: Why should the NDP government benefit from shipments from Alberta?" he asked during a media availability in Vancouver.

"People are already paying $1.50 a litre for their gas here. Thousands of British Columbia drivers are going down to Bellingham and Washington state to fill up their gas tanks. That situation, unfortunately, would get a whole lot worse without Alberta oil."

The United Conservative Party leader acknowledged that some oil companies in Alberta oppose the idea, but he said the province has to use the tools at its disposal to pressure B.C. Premier John Horgan's NDP government to "come to its senses."

"I don't suggest this as a beginning measure. This would be a last resort," he said in an interview later Monday.

Asked about the economic impacts to his province of turning off the taps to B.C., Kenney said he wasn't necessarily talking about a permanent measure. He added he's optimistic the Keystone XL pipeline will be built and provide a new outlet for Alberta oil.

U.S. President Donald Trump announced his approval of the TransCanada Corp. project last year.

Kenney also said he would consider slapping a toll on B.C.'s natural gas shipments through Alberta.

He said some Calgary-based companies that develop natural gas would not be happy with a toll, but added the job of an Alberta premier is to defend the province's economic future.

"I don't want a trade war. Albertans want free trade. But if the NDP in Victoria breaks the law, and blocks the export of our major product, we have to respond," he said.

He compared his stance to that of former Alberta premier Peter Lougheed, who in the early 1980s cut his province's oil production to punish Eastern Canada over the federal government's unpopular National Energy Program.

Alberta Premier Rachel Notley banned B.C. wines in response to the province's proposal to limit diluted bitumen shipments. But she lifted the ban after Horgan said he would ask the courts to decide whether it can bring in the restrictions.

Kenney said his party stands a good chance of forming a government in an election next year.

"My message to John Horgan is: I may very well be sitting across the table from you in 14 months. And if you're unable to come to an understanding with your fellow New Democrat Rachel Notley, just wait until you're sitting across the table from me."

Kenney also clarified his stance on supervised drug consumption sites, saying he respects the Supreme Court of Canada's decision that governments are obligated to license such facilities.

He said he's not oppose to licensing facilities that "try to reduce harm," but there needs to be more consultation with local communities and greater emphasis on stopping the drugs from entering Canada.

"My concern is that the focus has become almost single-mindedly on harm reduction, which I do not think is an adequate solution to the problem," he said.

In Edmonton, Notley met Monday with the members of her task force charged with coming up with strategies should B.C. or another jurisdiction take illegal or unwarranted actions against the oil industry.

Notley reiterated Alberta is keeping a close eye on Horgan's government and won't hesitate to bring back the wine boycott or take other more punitive measures if B.C. "starts playing more games."

Alberta officials will head to Ottawa this week to work with their federal counterparts on ways to get the Trans Mountain pipeline expansion moving, she said. The province will also intervene in Burnaby's appeal of a National Energy Board ruling on permits.

She said if B.C. gets court approval to dictate what goes into pipelines, "B.C. would trigger an internal Canadian trade war that would make what's going on with the United States today look like a tea party."

With files from Dean Bennett in Edmonton.