The White House has ordered mask manufacturer 3M to halt exports of N95 respirators to Canada and elsewhere that were bound for health care workers, the company said on Friday, pushing back against the US administration amid the Covid-19 pandemic and prompting hints of retaliation from Canadian Prime Minister Justin Trudeau.

There would be “significant humanitarian implications”, the firm said in a statement, in response to the White House’s invocation on Thursday of the Defence Production Act (DPA) requiring 3M to prioritise orders of N95 masks for US authorities.

Canadian Prime Minister Justin Trudeau said on Friday that he agreed with 3M that the White House order was “a mistake” and pointed out that thousands of Canadian nurses travelled to the US to work every day, adding that trade “goes both ways”.

CEO Mike Roman said his Minnesota-based company would comply with the DPA export ban, even as he warned of consequences for health workers around the world, including Canada, where he said 3M was the “primary supplier” of N95s.

N95 masks are a crucial piece of protective equipment for health workers dealing with Covid-19 patients and are in short supply globally.

The company said it had been working closely with the White House to meet its request to satisfy demand from the US Federal Emergency Management Agency (FEMA) ahead of others, and it was looking forward to implementing the order.

But the Trump administration also requested that 3M “cease exporting respirators that we currently manufacture in the United States to the Canadian and Latin American markets”.

“There are, however, significant humanitarian implications of ceasing respirator supplies to health care workers in Canada and Latin America, where we are a critical supplier of respirators,” it said.

3M also warned that cutting off exports would cause other countries to do the same, resulting in less overall availability of N95 masks in the US, not more.

“If that were to occur, the net number of respirators being made available to the United States would actually decrease,” 3M said.

“That is the opposite of what we and the administration, on behalf of the American people, both seek.”

In an interview with CNBC, Roman said the company was “net importing [N95 masks] into the US, and we’ve been telling the administration [that] for days and days”.

“We’re more than happy to shift our overseas production to the US, but there are going to be consequences on a humanitarian level. We are often the sole provider of those respirators in countries around the world,” he said.

“We will comply with DPA,” said Roman, “and we are taking steps to increase our imports, where we have that ability.”

US President Donald Trump said on Thursday that he anticipated issuing more orders under the Defence Production Act “in the very near future”.

“We assigned an element of the act against 3M and hopefully they'll be able to do what they are supposed to do,” he said.

Trudeau said in response to questions at a press conference on Friday that it “would be a mistake for both of our countries to limit access to goods and essential personnel”.

“3M has indicated it understands how important it is to deliver to Canada [and] it would be a mistake to restrict trade in essential goods,” he said.

He pointed out that thousands of nurses travelled to Detroit every day to work, and Canada also sent important medical equipment to the US.

“We are receiving essential supplies from the US but the US also receives essential supplies and products and indeed healthcare professionals from Canada every single day…these are things that Americans rely on,” he said.

3M said that last weekend the White House had requested that it increase imports of N95 masks from its overseas factories. It said that this week it obtained approval from China to send to the US 10 million N95 respirators manufactured by its mainland operation.

“We will continue to maximise the amount of respirators we can produce on behalf of US health care workers, as we have every single day since this crisis began,” the company said.