Japan staged a cyber security drill to test its computer systems against attacks in the lead up to the 2020 Summer Olympic Games in Tokyo, Reuters has reported.

A group of 50 specialists congregated at an emergency response center in the country's capital, host of the 2020 games, and at least 150 specialists were located offsite as the simulated attack took aim at 20 state ministries and agencies and 10 industry groups.

Japan's Prime Minister Shinzo Abe has made cyber security a priority but the country finds itself under almost constant attack by hackers, with the National Institute of Information and Communications reporting that cyber attacks grew from 7.8 billion in 2012 to 12.8 billion in 2013.

Last week, the government vowed to do more after information and technology from domestic companies had been leaked to rivals in other countries.