CHINESE hackers have gained access to secret designs for a slew of sophisticated US weapons programs, officials say.

The breaches are part of a broad Chinese campaign of espionage against top US defence contractors and government agencies, officials say, confirming a Washington Post account of a Pentagon report.

The Defence Science Board, a senior advisory group with government and civilian experts, concluded that digital hackers had gained access to designs for two dozen major weapons systems critical to missile defences, combat aircraft and naval ships, according to a Pentagon document cited by the Post.

The cyber spying gave China access to advanced technology and could weaken the US military's advantage in the event of a conflict, the board said on Tuesday.

The Pentagon advisory report stopped short of accusing Beijing of stealing the designs, but the conclusions help explain recent American warnings to the Chinese government.

"It's not clear how much of our stuff they got," a defence official told AFP on condition of anonymity.

The revelations of cyber espionage coincided with a report that Chinese hackers had stolen top-secret blueprints of Australia's new intelligence agency headquarters, including the layout for communications systems and server locations.

US officials are increasingly worried over digital spying from China and the White House said the issue would be high on the agenda when Chinese President Xi Jinping meets President Barack Obama next week.

"It is an issue that we raise at every level in our meetings with our Chinese counterparts," spokesman Jay Carney told reporters.

"And I'm sure will be a topic of discussion when the president meets with President Xi in California in early June."

The array of weapons designs that were targeted included the advanced Patriot missile system, a US Army program for shooting down ballistic missiles, and the Navy's Aegis missile defence system.

Designs for combat aircraft and ships, including the stealthy new F-35 fighter, the F/A-18 warplane, the V-22 tilt-rotor Osprey, the Black Hawk helicopter and the Navy's new Littoral Combat Ship, were also targeted.

The weapons programs affected are built by major defence contractors including Boeing, Lockheed Martin, Northrop Grumman and Raytheon.