Japan must make clear its criteria for restricting foreign direct investment if it hopes to attract capital from abroad, financial services minister Toshimitsu Motegi said Wednesday.

The Ministry of Economy, Trade and Industry got an earful from overseas investors after it ordered The Children's Investment Fund (TCI), a British hedge fund, to drop its bid to raise its 9.9 percent stake in Electric Power Development Co. to 20 percent in May.

Threats to national security, such as the TCI case, and certain businesses should be restricted, Motegi noted, but the criteria should be transparent nonetheless.