Chinese hackers have gained access to the designs of many major U.S. advanced weapons systems, according to a report prepared for the Defense Department and U.S. government and defense industry officials.

Australian media also accused Chinese hackers of stealing blueprints for Australia's new spy headquarters, The Washington Post reported.

Over two dozen major weapons systems whose designs were breached were programs critical to U.S. missile defenses and combat aircraft and ships, according to a previously undisclosed section of a confidential report prepared for Pentagon leaders by the Defense Science Board.

The electronic intrusions gave China access to advanced technology that could accelerate the development of its weapons systems and weaken the U.S. military advantage in a future conflict, warn experts.

The compromised weapons designs include the advanced Patriot missile system, the Navy's Aegis ballistic missile defense systems, the F/A-18 fighter jet, the V-22 Osprey, the Black Hawk helicopter and the F-35 Joint Strike Fighter.

The Chinese government has insisted that it does not conduct ­cyber-espionage on U.S. agencies or companies, the Post notes.

Chinese Foreign Ministry spokesman Hong Lei, asked about the Australian report, said China disapproved of hacking.

"China pays high attention to the cyber security issue and is firmly opposed to all forms of hacker attacks," Hong said at a daily briefing.

"Since it is very difficult to find out the origin of hacker attacks, it is very difficult to find out who carried out such attacks," Hong said. "I don't know what the evidence is for media to make such kinds of reports," he continued.