A Chinese national pleaded guilty to charges stemming from the hacking of trade secrets from US defense contractors, including plans for transport and fighter jets, officials said.

Su Bin, 50, had been charged in a 2014 indictment with hacking into the computer networks of Boeing and other contractors, as part of a scheme to steal plans for the F-22 and F-35 fighter jets and C-17 transport aircraft.

In a plea agreement filed in a California federal court, Su yesterday admitted to conspiring with two unnamed persons in China from October 2008 to March 2014 to gain unauthorized access to the computer networks of defense firms to obtain "sensitive military information and to export that information illegally from the United States to China," the Justice Department said in a statement.

Court documents did not indicate to whom Su was sending the plans, but the case highlighted growing concerns in the United States about Chinese hacking of American trade secrets, a topic which has been addressed by President Barack Obama and his Chinese counterpart Xi Jinping.

"Su Bin admitted to playing an important role in a conspiracy, originating in China, to illegally access sensitive military data, including data relating to military aircraft that are indispensable in keeping our military personnel safe," Assistant Attorney General John Carlin said.

"This plea sends a strong message that stealing from the United States and our companies has a significant cost; we can and will find these criminals and bring them to justice."

Su was initially arrested in Canada in July 2014 on a warrant based on a US request. He waived extradition and was sent to the United States in February 2016.

Su Bin, also known as Stephen Su and Stephen Subin, was a China-based businessman in the aviation and aerospace fields.