People hold signs calling for China to release Canadian detainees Michael Spavor and Michael Kovrig during a court appearance by Huawei's Financial Chief Meng Wanzhou. Kovrig and Spavor have been accused of acting together to steal state secrets and have been formally arrested in China.REUTERS/Lindsey Wasson

Montreal/Beijing - Canadian Prime Minister Justin Trudeau struck a defiant tone on Thursday following reports that authorities in Beijing had formally arrested an ex-Canadian diplomat and a businessman.

Beijing's arrest of Michael Kovrig and Michael Spavor has been seen as retaliation for Canada's detention in December of Meng Wanzhou, the chief financial officer of Chinese tech giant Huawei who currently faces extradition to the United States.

"The Chinese government is not following the same kinds of rules and principles that the large majority of democracies follow in regards to rules-based order, in regards to international relations," Trudeau told reporters in Paris on Thursday.

"We will consistently and always stand up for Canadians, particularly these Canadians who have been arbitrarily detained," Trudeau said. 

"But we will also make it very clear that we're not going to change our values or our systems, including the independence of our justice system, because China disagrees with our approach."

Kovrig and Spavor were taken into custody in China soon after Canada detained Meng in December, with both countries' actions straining relations between China, the US and Canada.

Kovrig and Spavor have been accused of acting together to steal state secrets and could be sentenced to death if convicted.

Chinese Foreign Ministry spokesman Lu Kang said Thursday the men were formally arrested "in recent days."

China is demanding Meng's immediate release and has called on the US to withdraw the extradition request and stop the "unreasonable suppression" of Chinese companies.

The US accuses Meng, Huawei, a US subsidiary and telecom equipment seller Skycom of committing bank fraud, wire fraud and conspiracy to commit money laundering. The charges are linked to possible violations of US sanctions against Iran.

The 47-year-old daughter of Huawei founder Ren Zhengfei made an appearance in a crowded courtroom in Vancouver on May 8 in the latest step in her much-anticipated extradition hearing.

Meng remains free on a 10-million-Canadian-dollar (7.4-million-US-dollar) bail and resides at one of the mansions in Vancouver she co-owns with her husband.

During her latest court appearance, Meng's lawyers asked that she be allowed to move to another mansion in Vancouver's Shaughnessy neighbourhood, which they said is more secure.

In the meantime, while Canadian officials have been allowed regular consular visits with Kovrig and Spavor, the two men have had no access to lawyers.

Guy Saint-Jacques, one of Canada's former ambassadors to China, told CBC News that the pair could soon face trial, though it is unclear when that may be, and their fates are likely already sealed,

According to Saint-Jacques, those formally accused in the Chinese system are found guilty in 99.9 per cent of cases.

"What we'll have to watch now is what is exactly the nature of the accusations and whether the penalty could include the death penalty," Saint-Jacques told CBC News. 

"We're dealing with some very difficult people."