Alberta NDP Leader Naheed Nenshi is calling on Premier Danielle Smith to cancel or postpone the province's upcoming separation referendum as Canada's trade war with the United States escalates.

Speaking to reporters in Calgary on Tuesday, Nenshi said its time to call of the referendum.

“The premier’s pandering to separatists just shows weakness; it shows that Canada is not united,” he said.

Albertans are scheduled to vote on October 19 on whether the provincial government should begin the legal process towards a future binding vote on leaving Canada.

Nenshi argued Canada needs to demonstrate unity as it faces renewed trade tensions with the United States.

The US has imposed tariffs on $28 billion worth of Canadian goods, while Canada has announced counter-tariffs taking effect September 8 on products including American steel, aluminium and consumer goods.

Smith has rejected calls to halt the referendum, saying hundreds of thousands of Albertans signed petitions seeking a vote.

“Citizens signed one of two petitions saying they wanted to have this question now, and that’s what the vote is going to be on October 19,” Smith said Saturday.

Smith has said she will vote for Alberta to remain in Canada.

Former Alberta premiers Rachel Notley and Jason Kenney are meanwhile co-chairing a Canadian Chamber of Commerce campaign advocating for Alberta to remain in Confederation.