Secret and highly sensitive and $630 million building blueprints outlining the layout of Australia's top spy agency's new headquarters have been stolen by Chinese hackers.

The Hacker NewsAccording to a report by the ABC's Four Corners, the blueprints included floor plans, communications cabling, server locations and the security systems.

The cyber attack, launched on a contractor involved in work at the site, is one of the reasons completion of the new building has been delayed. Companies including BlueScope Steel and Adelaide-based Codan, which makes radios for military and intelligence agencies, are also said have been targeted by the Chinese.

Under this major hacking operations, hackers successfully breached the Defence Department's classified email system, the Department of Prime Minister and Cabinet, and the Department of Foreign Affairs and Trade.

A separate attack on the Defence Department involved an employee sending a highly classified document from his desk computer to his home email account. Hackers had targeted the officer's home computer, allowing a copy of the document to be sent back to China once opened at home.

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