"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 begin to arbitrarily apply the death penalty in cases facing, as in this case, facing a Canadian", Justin Trudeau said in a news conference following the ruling.
"I won't comment specifically, because I may have a role down the road, but I will say that we are a rule of law country, and it's one of our most important principles and as minister of justice and attorney general for Canada I will always act to protect the rule of law", he told CBC News.
Her comments are the latest sign of a sharp cooling of China-Canada ties since Canada detained Meng Wanzhou, chief financial officer of Chinese telecommunications giant Huawei, on December 1 at the request of the United States.
Last week, Trudeau accused China of "arbitrarily and unfairly" detaining former diplomat Michael Kovrig and business consultant Michael Spavor, who were rounded up nine days after Canada arrested Meng.
The court said Schellenberg had conspired with others in an attempt to smuggle 222 kg (489.43 lb) of methamphetamine from China to Australia in late 2014.
Canada later updated its travel advisory for China, urging Canadians to "exercise a high degree of caution due to the risk of arbitrary enforcement of local laws".
Beijing issued a similar response hours later, calling on Chinese citizens to "travel cautiously" after a Chinese citizen was "arbitrarily detained on the basis of a request of a third-party country", an apparent reference to Meng's arrest.
A new trial was ordered in China's Liaoning province this week, where Schellenberg was found guilty once again and given a death sentence.
Chinese Foreign Ministry spokeswoman Hua Chunying expressed " strong dissatisfaction" with that.
Yet China has reacted with fury against Canada after Canadian law enforcement officers acted on the USA arrest warrant for Meng. The Chinese media began republicizing Schellenberg's case after Meng's detention.
Freeland said the cases of Schellenberg, Kovrig and Spavor will be "top of the agenda' for her next week when she travels to Davos, Switzerland to attend the World Economic Forum".
Schellenberg has chose to lodge an appeal, according to his lawyer.
China regularly executes citizens and foreigners convicted of drug-related offences.
But global rights groups condemned Schellenberg's sentence, with some saying it was too severe and may have been politically motivated.
On Monday, a court in the northeastern Chinese city of Dalian sentenced Schellenberg to death for drug smuggling. Freeland thanked countries and organizations _ Germany, France, the Netherlands, the European Union, the United States, Britain, Australia, Estonia, Lithuania and Latvia _ for "publicly coming out and speaking against these arbitrary detentions".