A top Chinese executive being held in Canada can make "strong arguments" against extradition to the United States, partly due to remarks made by US President Donald Trump, Canada's ambassador to China has said.

In comments to Chinese media broadcast on Wednesday, Canadian envoy John McCullum said that Huawei executive Meng Wanzhou's extradition "would not be a happy outcome".

Meng was arrested on December 1 while transferring between flights at Vancouver airport and is currently under house arrest. She was detained at the request of the US over alleged violations of US sanctions on Iran.

Last month, President Trump said he might abandon the Meng case if it helped to serve US national security interests or helped to secure a trade deal with China.

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In response, Canada's Foreign Minister Chrystia Freeland warned Washington not to politicise extradition cases.

McCallum said Meng had "quite good arguments on her side", the first of which was "political involvement by comments from Donald Trump in her case".

McCallum also noted that Canada has not applied the same sanctions against Iran as the US.

"Canada does not sign onto these Iran sanctions. So I think she has some strong arguments she can make before a judge," he said.

Meng's arrest has severely damaged ties between Ottowa and Beijing, which has demanded her immediate release. Her arrest has also infuriated China's president.

China detained former Canadian diplomat Michael Kovrig and Canadian entrepreneur Michael Spavor on December 10 in an apparent attempt to pressure Canada to release Meng.

Meng is Huawei's chief financial officer and the daughter of its founder, Ren Zhengfei.

Huawei said it is a private company but the US alleges it has close ties to the Chinese state and military. It is considered one of the country's most successful international enterprises, operating in the high-tech sphere where China hopes to establish itself as a major global player.

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"What I do know is that President Xi Jinping was very angry about this and so others in the Chinese government have taken the lead from him," McCallum said. "I don't know exactly why. Maybe it's because Huawei is a national flagship company of China. It's not just any company."

David Mulroney, Canada's former ambassador to China, called McCallum's remarks "mind-boggling".

Mulroney said giving advice to a judge is completely inappropriate when the government has been saying that Meng's extradition is up to judicial authorities.

"It raises some troubling questions about whether there is two track messaging going on," he said. "It's beyond me. I can't imagine what his intent was."

Mulroney said Canadian Prime Minister Justin Trudeau and Foreign Minister Chrystia Freeland have to distance themselves from the remarks.

"It's a setback. It undermines that Canada is playing this by the book," he said.

Trudeau and Freeland have stressed they can't interfere politically in the case.

"With respect to Meng Wanzhou, Huawei's Chief Financial Officer, Canada is conducting a fair, unbiased and transparent legal proceeding. There has been no political involvement in this process. Canada respects its international legal commitments, including by honoring its extradition treaty with the United States," Freeland spokesman Adam Austen said in a statement.