Chinese foreign ministry spokesman Zhao Lijian said that Canada's claims were groundless
Canada on Wednesday identified state-sponsored programs in China, Russia, Iran and North Korea as major cyber crime threats for the first time, and said it feared foreign actors could try to disrupt power supplies.
The Communications Security Establishment (CSE) signals intelligence agency said the programs posed the greatest strategic threat to Canada.
"State-sponsored cyber activity is generally the most sophisticated threat," CSE said in its second national cyber threat assessment.
CSE's first study, released in 2018, mentioned foreign-based actors without identifying them. In July, Canada, Britain and the United States accused Russian-backed hackers of trying to steal Covid-19 vaccine data.
China and Russia have repeatedly denied trying to break into other nations' critical infrastructure.
Chinese foreign ministry spokesman Zhao Lijian said on Thursday that Canada's claims were groundless and China is itself a victim of cyber attacks.
Canada's relations with China have soured notably over the last two years.
"We certainly have a long history of noting behavior from China that isn't in accordance with what our expectations are," Scott Jones, head of cyber security at CSE, told reporters.
Jones did not answer directly when asked why the four nations had been named.
CSE said it was very unlikely hackers would try to cause major damage or kill people in the absence of war.
But they "may target critical Canadian organizations to ... pre-position for future activities, or as a form of intimidation," it added.
"State-sponsored actors are very likely attempting to develop the additional cyber capabilities required to disrupt the supply of electricity."
In 2019, Russian-associated actors probed US and Canadian electricity utilities, it added.
CSE said the threat of potential hacks was serious given how many people were relying on digital services amid the coronavirus pandemic.
CSE is probing whether China's Huawei Technologies Co Ltd can supply equipment for next-generation 5G networks. The United States and other close allies have moved to block Huawei, saying its gear could contain backdoors allowing access for spies.