The revised advisory cautioned travellers of the "risk of arbitrary enforcement of local laws", and noted that the "safety and security situation could change with little notice".
A Chinese court sentenced a Canadian man to death on accusations of drug trafficking, a move that could escalate tensions between the two nations stemming from the arrest of a Huawei Technologies Co. executive.
Meanwhile, Canadian Prime Minister Justin Trudeau vowed to "intercede" in the case related to the Canadian drug trafficker, South China Morning Post reported.
The court said Schellenberg is entitled to appeal his verdict and sentencing within 10 days.
Schellenberg had been sentenced to 15 years in jail for smuggling methamphetamines just before Meng's arrest, but appealed the decision.
Meng, 46, is the daughter of Huawei's founder and her detention angered China and soured its relations with both Canada and the US.
According to the court, Schellenberg was dispatched to Dalian by drug traffickers in November 2014 to orchestrate the smuggling of more than 222 kilograms (489.4 pounds) of methamphetamine from the Chinese port city to Australia.
In an opening statement, Schellenberg said he had come to China after travelling through Southeast Asia, including Laos, Myanmar, Malaysia, Singapore and Thailand. This is because in his own country, Ansley said, the Chinese leader can just pick up the phone "and tell the chief judge of the court what is required and virtually dictate the action to the court".
Despite being sentenced in 2016, Schellenberg was sent back to trial and re-sentenced on Monday, this time to the death penalty.
"It is of extreme concern to us as a government, as it should be to all our worldwide friends and allies, that China has chosen to arbitrarily apply [the] death penalty", he told reporters in Ottawa.
The tempo of Schellenberg's case has accelerated since Meng's arrest.More news: Storm Punishes Swath Of U.S. With Snow, Ice And Freezing Rain
At the retrial, prosecutors said that Schellenberg was heavily involved in a failed attempt to smuggle methamphetamines to Australia in pellets stuffed inside tires.
Schellenberg can appeal against the sentence in an upper court.
"It appears the Government of China may be politicizing this case in retaliation for the arrest of Huawei executive Meng Wanzhou".
Trudeau said last week that Chinese officials were not respecting Kovrig's diplomatic immunity. Meng is out on bail in Canada awaiting extradition proceedings that begin next month.
"According to the Vienna Convention of Diplomatic Relations and global law, he is not entitled to diplomatic immunity", Hua said at a daily briefing.
Days after Meng's arrest, Kovrig and Canadian businessman Michael Spavor were detained on vague national security allegations.
"I would like to suggest that Canada's relevant people should first study and seriously research the Vienna Convention on Diplomatic Relations and the International Law before they express their views, instead of being plausible and exposing themselves to ridicule", said Hua.
Donald Clarke, a China law expert at the George Washington University Law School, described the Canadian detainees - including Schellenberg - as "hostages".
"On that, I think Canada's in relatively good position because we traditionally have been excellent at banding together and creating meaningful alliances and institutions with a large number of very powerful countries".
Canada made the arrest at the US' request.