Ottawa ramped up its response to the COVID-19 pandemic on Monday with sweeping new travel restrictions meant to prevent the spread of the disease — but stopped short of banning travellers from the U.S.

That creates a loophole that risks further spread of the disease, according to critics.

"We remain concerned that access from visitors from the U.S. continues to be allowed," said B.C. Health Minister Adrian Dix, citing the situation in neighbouring Washington State, where there are more confirmed cases of COVID-19 than in all of Canada, and 10 times as many deaths.

"I support all the measures the prime minister has taken and I'd like him to take one more — which is to also apply it to the United States, to visitors and non-essential travel."

Green Party parliamentary leader Elizabeth May also called for Prime Minister Justin Trudeau to ban U.S. citizens.

"The situation in America is likely to be far worse than here, and the sooner we protect ourselves the better," said May.

Trudeau's announcement barred all foreign nationals from boarding flights to Canada, except for permanent residents, immediate family of Canadian citizens, U.S. citizens, air crew and diplomats.

"The level of integration of our two countries is quite particular," Trudeau said, "which is why we need to do some more work in order to ensure that we're doing what we need to do in the right way."

In 2019, 25 million travellers entered Canada from the U.S., according to Statistics Canada. The majority — 16.7 million — did so by car. Another 5.6 million arrived by plane.

Total trade with the U.S. was valued at over $752 billion.

Preserving that freedom of movement is necessary to maintain trade says Dennis Darby, president of the industry association Canadian Manufacturers and Exporters.

"This is essential for continued access to critical supply chain components including for food processing and medical device production," Darby said in a statement.

Vehicles enter the U.S. at the Detroit-Windsor Tunnel in Detroit, on Monday. In 2019, 25 million travellers entered Canada from the U.S., according to Statistics Canada. (Paul Sancya/The Associated Press)

In addition, Canada imports 75 per cent of its medical equipment, including X-ray machines and ventilators. Around half of those imports come from the U.S., according to the U.S. Department of Commerce.

"Whether it's the truckers going back and forth, whether it's people going back and forth between the plants … it makes sense [that] we need to be able to have people go back and forth from Canada and the U.S.," Darby told CBC News.

But Trudeau's cabinet was also likely thinking about how Washington would react to a blanket ban on its citizens, said James Moore, a former cabinet minister under Prime Minister Stephen Harper.

"It's one thing to have a travel ban, but it's another thing for the president of the United States to see that as a vote of non-confidence on the global stage of his handling of the coronavirus," said Moore.

"The message that Canada would be sending to the world is that you can't trust the United States."

Such a move would risk provoking a reaction from President Donald Trump that could damage the Canadian economy and lead to shortages, especially if the president decided to restrict trade in essential goods, Moore said.

"Donald Trump has shown an ability to — without any rationality — put in place barriers to trade and access to the U.S. market for political reasons," he said. Moore cited Trump's steel tariffs on Canadian steel as an example of the kind of economic pain the U.S. could impose on Canada.

"An absolute public panic could set in if we go into grocery stores and the shelves are not being restocked and people aren't getting their medicines," he said.