A Canadian minister's sudden resignation on Tuesday turned vague allegations of interference in the criminal prosecution of an engineering giant into a deepening political crisis for Prime Minister Justin Trudeau's Liberals.

A group of more than 100 former diplomats and academics have signed an open letter to Chinese President Xi Jinping calling for the release of two Canadians who have been detained on allegations of espionage.

Prime Minister Justin Trudeau renewed calls for the release of Saudi blogger Raif Badawi after meeting his wife on Friday, calling the issue "a priority" for him and all Canadians.

Canada urged Beijing on Tuesday to grant clemency to a Canadian sentenced to death for drug trafficking, after his sentence reignited a diplomatic dispute that began last month.

The young Saudi woman who fled her family seeking asylum abroad is scheduled to land in Canada on Saturday after successfully harnessing the power of Twitter to stave off deportation from Thailand.

A third Canadian citizen has been detained in China, a Canadian newspaper reported Wednesday, amid a diplomatic spat between Beijing and Ottawa over the arrest of a Chinese telecom executive.

Ottawa on Thursday identified the second Canadian questioned in China as Michael Spavor, and said he has been missing since he last made contact with Canadian officials.

Canada condemned Saudi Arabia's account of the death of dissident journalist Jamal Khashoggi as inconsistent and not credible on Saturday, calling for a "thorough" investigation.

Nearly a century of marijuana prohibition came to an end Wednesday as Canada became the first major Western nation to legalize and regulate its sale and recreational use.

Saudi Arabia's diplomatic brawl with Canada has exposed what Western officials call "new red lines" in their engagement with the oil-rich kingdom, deterring nations from publicly criticising its human rights record.