The Saskatchewan government refuses to talk to the Alberta government after banning Alberta licence plates on road construction sites, says Alberta's economic development minister.

"We learned about this through the media. They did not give us a heads up at all," Deron Bilous said Thursday.

"My office reached out to both the trade minister of Saskatchewan and the infrastructure transport minister ... before we made a comment as the government of Alberta.

"They still have not returned our calls."

On Thursday, Bilous repeated his threats to take Saskatchewan to court within a week if the province doesn't back down.

"The clock is ticking," he told reporters at the legislature.

Bilous called the ban desperate and said it violates interprovincial free trade rules. He added there may be "consequences" in addition to the court case, but wouldn't provide specifics.

"You've got Brad Wall, who is a premier, who is quite desperate to change the channel from his bad-for-business budget," Bilous said in an interview with CBC Radio's Edmonton AM. "And so they've decided to come after Alberta and Alberta workers.

"It's quite absurd, when you think about it. Alberta's economy is bigger than both B.C. and Saskatchewan's combined, so starting a trade war with your bigger, older brother is never a wise thing to do."

Wall fine with a court battle

Wall defended the decision Thursday during question period in Regina.

"No, we didn't check with Alberta. We defended the interest of the people of Saskatchewan."

Later, Wall said he would welcome a court challenge.

"We won't be backing off on it," he said. "First of all, we think it doesn't necessarily violate trade agreements, because this is the treatment our contractors get when they are working in Alberta.

"They are asked to permit they are asked to plate. We think it's fair to ask the same thing of Alberta folks working here."

The Saskatchewan government is banning vehicles with Alberta plates from road construction sites in the province. (The Muskegon Chronicle, Ken Stevens/AP)

Wall mentioned a recent trade dispute between the two provinces over beer. His government argued a new beer tax was hurting Saskatchewan brewers. Saskatchewan won the court case, which is now being appealed by Alberta.

"They set this example," Wall said. "If you're going to live by the protectionist sword, you're going to have to face other provinces that will stand up and defend their economy and their sectors."

'They're going to lose this fight'

Saskatchewan announced Wednesday that it is banning workers with Alberta licence plates from all new road projects.

"I've called on Brad Wall to smarten up and kill this ridiculous and discriminatory restriction," Bilous said.

"They're going to lose this fight."

The ban only applies to Alberta. Existing projects will not be affected. The Ministry of Highways said it is singling out Alberta for a reason.

"Saskatchewan operators feel forced to register their vehicles in Alberta if they want to do business there," Saskatchewan Infrastructure Minister David Marit said Wednesday. "Today's announcement just levels the playing field."

Saskatchewan Minister of Highways and Infrastructure David Marit said his decision to ban Alberta licence plates from new construction projects was shaped by concerns from the province's construction industry. (CBC)

Saskatchewan also said that since Alberta does not have a provincial sales tax, Alberta drivers don't pay PST when registering vehicles as Saskatchewan motorists do — an unfair trade advantage for Alberta contractors.

Now Alberta contractors will be required to get Saskatchewan plates and pay PST when they register their vehicles.

According to a statement from the Saskatchewan government, the amount of PST will be prorated, based on the amount of work Alberta contractors do within the province.

Alberta Trade Minister Deron Bilous demands Saskatchewan kill restrictions that ban workers with Alberta plates from new road projects. 0:54

Bilous said the ministry's claims are bogus. Saskatchewan contractors working in Alberta are not required to change plates or go through any additional vehicle registrations, he said, adding that Saskatchewan's trade minister might be "confused."

"Their accusations, we've gone through our own departments and found it to be untrue, so the fact that they're trying to pick a fight with Alberta, I think it's a little ridiculous. In fact, it's quite absurd," Bilous said.

And, he said, "trying to punish Alberta for not having a PST is ridiculous."

Notley calls policy 'ridiculous'

The plate feud is the latest cross-boundary sniping between Wall's right-of-centre government and Premier Rachel Notley's left-leaning NDP.

Notley joked about the controversy at the start of her speech to the Edmonton Chamber of Commerce Thursday.

"If any of you drove here, and have a Saskatchewan licence plate, you might want to move your car, because we are towing," she said to laughter from the crowd.

"I'm just kidding, of course. Everybody is welcome here in Alberta."

Wall said Notley's government set a projectionist tone in 2016 when it didn't go along with open procurement, he said all other provinces were in favour.

Notley was asked about that point by reporters on Thursday.

"That doesn't apply at all to Saskatchewan and Brad Wall knows it. That is, I believe now explanation number four for this ridiculous piece of public policy coming from Saskatchewan in under 12 hours," Notley said.

Fishing for controversy

Political analyst Paul McLoughlin said the spat is an interesting manifestation of a complicated, three-way political feud between Notley's NDP government, Alberta's United Conservatives and the reigning Saskatchewan Party.

"There is a little partisan game going on here," McLoughlin said Thursday. "It's more than a rivalry; it's political friction between Saskatchewan and Alberta."

It's like Saskatchewan took the bait and the NDP said, 'Fine, let's reel this one in' - Paul McLoughlin , political analyst

By making Saskatchewan look foolish, the NDP government has managed to cast shade on Alberta UCP leader Jason Kenney and his newly formed party, said McLoughlin.

All three parties are fishing for a little bit of controversy, he said.

"You have to remember that Brad Wall is a hero to conservatives across the country — including Jason Kenney and the United Conservative Party — so any opportunity the NDP has to generate outrage about the terrible things they're doing in Saskatchewan, they go after it with relish and glee.

"It's like Saskatchewan took the bait and the NDP said, 'Fine, let's reel this one in.'"

Terry Parker, executive director for Building Trades of Alberta, which represents 75,000 workers, and former executive director for Building Trades of Saskatchewan, said he was baffled by the move.

He said he hasn't heard any complaints, on either side of the border, about the licensing issue, and the announcement came as a shock to people working in the construction industry.

'Unnecessary' argument

Saskatchewan's argument that taxes aren't being paid by Alberta contractors is "unnecessary," said Sandy Johnson, owner of North Star Fleet Solutions Inc., a Calgary company that specializes in consumption taxes and licence fees for inter-jurisdictional carriers.

"This whole system of tax distribution is to create a level playing field," Johnson said.

"It doesn't matter if you're from Alberta or if you're from Florida. If you are competing for the same traffic, or a contractor competing for the same job, you are subject to taxes and licence fees."

She said any Alberta contractors circumventing the system are subject to audit and would be in breach of contracts in Saskatchewan.