A top Chinese diplomat warned Canada Thursday against granting asylum to Hong Kong democracy protesters, adding that doing so could jeopardize the "health and safety" of Canadians living in the southern Chinese financial hub.

The remarks by Cong Peiwu, Beijing's Ottawa envoy, prompted a rebuke from Canada's foreign minister, further escalating tensions between the two countries.

Cong was responding to reports that a Hong Kong couple who took part in last year's huge and sometimes violent protests had been granted refugee status.

The landmark decision makes it likely other Hong Kongers will be given sanctuary in Canada, which has emerged as a top destination for those fleeing Beijing's crackdown.

"We strongly urge the Canadian side not (to) grant so-called political asylum to those violent criminals in Hong Kong because it is the interference in China's domestic affairs. And certainly, it will embolden those violent criminals," Cong said in a video press conference.

"So if the Canadian side really cares about the stability and the prosperity in Hong Kong, and really cares about the good health and safety of those 300,000 Canadian passport-holders in Hong Kong, and the large number of Canadian companies operating in Hong Kong SAR, you should support those efforts to fight violent crimes," Cong said.

When asked by reporters if that latter comment was a threat, Cong replied: "That's your interpretation."

Canada's Foreign Minister Francois-Philippe Champagne described Cong's comments as "totally unacceptable and disturbing".

"I have instructed Global Affairs to call the ambassador in to make clear in no uncertain terms that Canada will always stand up for human rights and the rights of Canadians around the world," he said in a statement carried by the Globe and Mail and other Canadian news outlets.

China and Canada are marking 50 years since they forged diplomatic ties -- but those relations are deeply strained.

Ties plummeted following Canada's arrest of Meng Wanzhou, chief financial officer of Chinese telecoms giant Huawei and daughter of its founder.

Meng was arrested on a US warrant in December 2018 during a stopover in Vancouver and is charged with bank fraud related to violations of US sanctions against Iran. 

She has been fighting extradition ever since.

Canadian former diplomat Michael Kovrig and businessman Michael Spavor were arrested in China on spying charges soon afterwards, disappearing into Beijing's opaque judicial system.

Western governments see the detention of the two Canadians as direct retaliation by Beijing. 

On Tuesday, Canadian Prime Minister Justin Trudeau hit out at Beijing for what he said was its "coercive diplomacy" as well as the ongoing crackdowns in Hong Kong and on Uighur Muslims in Xinjiang. 

Cong rejected Trudeau's comments at his Thursday press conference. 

"There is no coercive diplomacy on the Chinese side," he said.

"The Hong Kong issue and the Xinjiang-related issue are not about the issue of human rights. They are purely about internal affairs of China, which brooks no interference from the outside," he added.