High-level Chinese hackers recently tried to break into a key Canadian computer system, forcing Ottawa to isolate it from the main government network, a senior official said on Tuesday.
Chief government information officer Corinne Charette said there was no evidence to suggest the attack on the National Research Council of Canada (NRC) computers had compromised overall government security.
The NRC is the Canadian government's leading research and technology organisation, which works with major firms such as aircraft and train maker Bombardier.
Charette said Canada had recently "detected and confirmed a cyber intrusion on the IT infrastructure of the National Research Council of Canada by a highly sophisticated Chinese state-sponsored actor", but gave no further details of the attack. She said although NRC computers did not operate within the overall government system, they had been isolated as a precautionary measure.
"We have no evidence that data compromises have occurred on the broader government of Canada network," she said in a statement.
The attack was not the first hacking attempt in Canada that has been linked to China. In September 2012, Canada said it was aware hackers had breached security at a domestic manufacturer of software used by big energy companies.
At the time Ottawa declined to comment on a report by a cyber security news site saying evidence suggested a Chinese group was responsible.
Beijing, frequently accused of launching state-sponsored cyber-attacks against rival-countries dismisses the latest accusations.