HACKERS have reportedly launched an unprecedented cyberattack on the Canadian government, penetrating the computer systems of two key agencies and forcing them offline.

The Canadian Treasury Board issued a brief statement recognising it had detected an “unauthorised attempt to access its networks” but did not elaborate.

“Employee access to the internet has been limited for the time being,” said Treasury Board spokesman Jay Denney.

CBC News cited “highly placed sources” in conservative Prime Minister Stephen Harper’s government as saying that the cyberattacks, first detected in January, were traced to computer servers in China.

The hackers managed to penetrate the computer systems at the Finance Department and the Treasury Board, according to CBC. They also successfully overpowered computers in the offices of senior government officials in a bid to steal passwords that hold the key to government data systems.

Although CBC said it could not determine whether the attackers were Chinese or simply other nationals who used China-based servers, CTV television said they were “Chinese government hackers”.

It cited sources as saying the Canadian Security Intelligence Service has advised government officials not to name China as the origin of the attacks, or even discuss the matter.

Chinese espionage has become a “major problem” for Canada and other countries, a senior government official told CTV.

CBC said it remained unclear whether the attackers were able to access other computer networks, such as those containing Canadians’ tax and health records along with other personal details.

Upon learning of the attack, Canadian cybersecurity officials shut down internet access at the two departments as they scrambled to prevent hackers from stealing more information via the internet, it added.

“There are no indications that any data relating to Canadians was compromised by this unauthorised attempt to access the TBS (Treasury Board of Canada Secretariat) network,” said Denney.

“The government of Canada has plans in place to prevent, minimise and address the impacts of cyber threats.”