An expert has warned that Japanese public institutes have a cavalier attitude toward the protection of advanced technologies, a week after the arrest of a Chinese researcher for an alleged data leak.

"If they don't change, their data will be stolen freely," said Kazuto Suzuki, professor of international politics and economics at the University of Tokyo's Graduate School of Public Policy.

Tokyo police arrested Quan Hengdao, 59, on June 15 for allegedly emailing to a Chinese company research data of the National Institute of Advanced Industrial Science and Technology, or AIST, where he was working as a researcher.