Prosecutors on Wednesday raided the offices of Japan Highway Public Corporation, a state-run organisation, for alleged involvement in one of Japan's biggest and most deeply entrenched bid-rigging scandals.

The Fair Trade Commission, Japan's anti-monopoly watchdog, on Wednesday filed a criminal complaint against three companies suspected of pre-arranging the outcome of bids financed by Japan Highway. The companies are Mitsubishi Heavy, the country's leader in the heavy industry sector, Ishikawajima-Harima Heavy Industries and Yokogawa Bridge.