Japanese government and other organisations recorded 12.8 billion cyber-attacks in 2013, up 64.1% from the 7.8bn registered the previous year.
According to the country's National Institute of Information and Communications Technology (NICT), the country saw a rise in cyber-attacks deriving from China, the US, and other emerging countries.
The institute also noted that the rise in cyber-attacks, comprising distributed denial of service (DDoS), was partly due to more sensors installed to maintain its surveillance, according to reports cited by Japan's Kyodo News agency.
NICT also detected cyber-attacks on some government servers during May 2013 in the wake of criticism from hacktivist group, Anonymous, over the country's whaling actions.
However, they were not able to trace the actual locations of hackers as the PCs used to carry-out attacks could be remotely controlled.