Leaked documents reportedly show that Chinese spies hacked large amounts of data relating to the design of the F-35 Joint Strike Fighter jet.
Media reports suggest the alleged cyber theft is revealed in documents leaked to the German magazine Der Spiegel by former US security analyst Edward Snowden.
The F-35 is a stealth bomber developed by the US-based defence firm Lockheed Martin. The Royal Air Force is among the major customers for the jet.
The Sydney Morning Herald cites one document as saying that the theft amounts to "many terabytes of data" including information about the F-35's radar systems, engines and method for cooling exhaust gases.
Former U.S. intelligence contractor Edward Snowden has received a three-year residence permit from Russia, his Russian lawyer has said.
"The decision on the application has been taken and therefore starting Aug. 1 2014 Edward Snowden has received a three-year residential permit," Anatoly Kucherena said.
Academy Award winning director Oliver Stone is make a film about Edward Snowden, one of two high-profile movies in the works about the National Security Agency whistleblower.
Stone said he planned to adapt The Snowden Files: The Inside Story Of The World's Most Wanted Man, a book by Guardian journalist Luke Harding.
The Platoon director will have stiff competition however: Sony Pictures purchased the big-screen rights to Glenn Greenwald's No Place To Hide: Edward Snowden, The NSA And The US Surveillance State. The film is being produced by James Bond producers Barbara Broccoli and Michael G Wilson.
Stone has advocated for the former NSA contract systems analyst, who is living in Russia on a temporary grant of asylum after leaking massive amounts of agency documents to the media.
"To me, Snowden is a hero because he revealed secrets that we should all know, that the United States has repeatedly violated the Fourth Amendment," Stone said at the Karlovy Vary Film Festival in the Czech Republic.
American opinion on whether computer analyst Edward Snowden patriot or traitor has swung significantly after an interview was aired on US television.
Snowden leaked US intelligence information but in the interview he insisted he was a patriot. During the course of it, he managed to persuade people watching at home.
Whistleblower Edward Snowden has told NBC News he is "comfortable" with his actions in revealing details of the US National Security Agency's surveillance programme.
However Snowden, who is now living in exile in Russia, admitted he does feel a "sense of loss" at not being able to return to the US.
US Secretary of State John Kerry invited Snowden to "man up and come back to the United States."
"The bottom line is this is a man who has betrayed his country, who is sitting in Russia, an authoritarian country where he has taken refuge," Kerry told the CBS network.
"If he has a complaint about what's the matter with American surveillance, come back here and stand in our system of justice and make his case," Kerry said.
"There have been times throughout American history where what is right is not the same as what is legal," Edward Snowden told NBC News.
Former US spy agency contractor Edward Snowden has told a US television interviewer he would like to go home from asylum in Moscow, but that if necessary he would seek to extend his stay in Russia.
US officials said he was welcome to return to the United States if he wanted to face justice for leaking details of massive US intelligence-gathering programmes.
"If I could go anywhere in the world, that place would be home," Snowden told NBC Nightly News anchor Brian Williams in an excerpt from the interview that aired on Wednesday.
Former CIA operative Edward Snowden appeared on Russian television today to ask Vladimir Putin whether his government is engaged in the sort of mass surveillance he claims the US government is involved in.
Mr Putin tells Snowden, who appears via video link, that there is no "indiscriminate" mass surveillance in Russia and that "in accordance with the law, there cannot be".
Edward Snowden has issued a statement after the Guardian and Washington Post were awarded the Pulitzer Prize for public service in honour of their coverage of the NSA revelations.
"Today's decision is a vindication for everyone who believes that the public has a role in government," the whistleblower said.
"We owe it to the efforts of the brave reporters and their colleagues who kept working in the face of extraordinary intimidation," he added.
"This decision reminds us that what no individual conscience can change, a free press can. My efforts would have been meaningless without the dedication, passion, and skill of these newspapers, and they have my gratitude and respect for their extraordinary service to our society.
"Their work has given us a better future and a more accountable democracy," Mr Snowden said.