SYDNEY, May 12 (Reuters) - A former U.S. Marine pilot fighting extradition from Australia on U.S. charges of training Chinese military pilots to land on aircraft carriers, unknowingly worked with a Chinese hacker, his lawyer said.

Daniel Duggan, 55, a naturalised Australian citizen, feared requests by Western intelligence agencies for sensitive information were putting his family at risk, the lawyer said in a legal filing seen by Reuters.

The lawyer's filing supports Reuters reporting linking Duggan to convicted Chinese defence hacker Su Bin.

Duggan denies the allegations that he broke U.S. arms control laws. He has been in an Australian maximum security prison since his 2022 arrest after returning from six years working in Beijing.

U.S. authorities found correspondence with Duggan on electronic devices seized from Su Bin, Duggan's lawyer Bernard Collaery said in the March submission to Australian Attorney General Mark Dreyfus, who will decide whether to surrender Duggan to the U.S. after a magistrate hears Duggan's extradition case.

The case will be heard in a Sydney court this month, two years after his arrest in rural Australia at a time when Britain was warning its former military pilots not to work for China.

Su Bin, arrested in Canada in 2014, pleaded guilty in 2016 to theft of U.S. military aircraft designs by hacking major U.S. defence contractors. He is listed among seven co-conspirators with Duggan in the extradition request.

Duggan knew Su Bin as an employment broker for Chinese state aviation company AVIC, lawyer Collaery wrote, and the hacking case was "totally unrelated to our client".

Although Su Bin "may have had improper connection to (Chinese) agents this was unknown to our client", Duggan's lawyer wrote.