Open this photo in gallery John McCallum told the South China Morning Post that he warned Beijing that any more punitive measures against Canada could help oust Liberal Prime Minister Justin Trudeau from power. Sean Kilpatrick/The Canadian Press

Former Canadian envoy to Beijing John McCallum says he has cautioned Chinese officials that further sanctions against Canada over the arrest of Huawei executive Meng Wanzhou could help spur the election of a Conservative government, which would be far less favourable to Beijing.

The former ambassador, who was fired in January after he publicly waded into the Huawei extradition case, revealed his discussions during an interview on Canada-China tensions with the South China Morning Post this week. The Hong Kong newspaper said Mr. McCallum had been speaking to “former contacts at China’s Ministry of Foreign Affairs.”

Last December, Canada detained Ms. Meng, Huawei’s chief financial officer, at the request of U.S. authorities in relation to violations of U.S. sanctions against Iran. She is awaiting an extradition hearing scheduled for January 2020.

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Beijing responded by arresting two Canadians – Michael Spavor and Michael Kovrig – on alleged national-security violations and by restricting imports of Canadian canola, pork and beef.

Mr. McCallum told the South China Morning Post that he warned Beijing that further punitive measures against Canada could help oust Liberal Prime Minister Justin Trudeau from power. A Canadian federal election is expected in October.

“Anything that is more negative against Canada will help the Conservatives, [who] are much less friendly to China than the Liberals,” Mr. McCallum told the South China Morning Post.

“I hope and I don’t see any reason why things will get worse. It would be nice if things will get better between now and [Canada’s federal] election [in October].”

Mr. McCallum could not be immediately reached for comment Thursday.

He is a veteran Liberal Party insider who served as cabinet minister in three Liberal governments, including Mr. Trudeau’s.

Conservative Leader Andrew Scheer said Mr. McCallum’s comments invite foreign interference in Canadian elections.

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“This is a senior Liberal conveying the message to China that they should help the Liberals get elected because it would be in China’s best interest,” Mr. Scheer said.

“Is this what the Liberals are telling China? ‘Go easy on us for a couple of months'?"

David Mulroney, another former Canadian ambassador to China, said it’s currently unclear to Beijing whether Mr. McCallum still speaks for the Canadian government and that Mr. Trudeau should issue a statement indicating that he does not speak for government.

Foreign Minister Chrystia Freeland’s office, asked for comment on Mr. McCallum’s remarks, did not speak directly to his point about election prospects. Instead, deputy press secretary Marie-Pier Baril said: “When it comes to China, our government’s priority is the welfare of Michael Kovrig and Michael Spavor, who have been arbitrarily detained."

She said the outpouring of support for Canada among this country’s allies. "Our government has been clear about our principles, our commitment to the rule of law, and our deep concern for our citizens who have been detained. We will continue to stand up for them.”

Ms. Baril also said on the Meng case, Canada has carefully “abided by its extradition treaty commitments, in accordance with the rule of law” and that “there has been no political interference in this case.”

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Mr. McCallum lost his job as ambassador earlier this year after he told media that he believed Ms. Meng had strong legal arguments in her favour to avoid being extradited to the United States. He had also publicly speculated that U.S. President Donald Trump might intervene and cut a deal that would result in her freedom.

He urged Canadian officials and business leaders in the South China Morning Post interview to continue to conduct visits that could expand their relationship with China, so that Canadian firms would be poised to benefit when regular bilateral ties resume.

“Canada is in China for the long run … this problem will pass,” he said. “It’s important for Canadian business people not just to come to China but to come often … especially when the going is tough.

“This will put our companies in a good position to do well when the going improves.”

In late June, China also announced it was temporarily suspending all meat exports from Canada, citing the discovery of a banned substance in frozen pork from this country. The drug at issue is approved for use in Canada and the United States, but not in Europe, Russia or China.

A subsequent Chinese investigation found official veterinary health certificates attached to the batch of pork exports were counterfeit, reflecting “obvious safety loopholes” in Canada’s export system, the Chinese embassy said.

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Canada is investigating the falsified meat export certificate.

In early June, McMillan LLP announced that Mr. McCallum had joined the law firm as a strategic adviser.

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