The Fair Trade Commission searched the offices of Penta-Ocean Construction Co. and Wakachiku Construction Co. on Thursday on suspicion of rigging bids for port projects in Nagasaki Prefecture, industry sources said.
The FTC also searched more than 20 local construction companies in the prefecture, suspecting that they conspired to preselect winners for competitive bids made on projects ordered by the prefectural government, the sources said.
Nagasaki, with its numerous islands, has 286 fishing ports, the most among all prefectures, with the prefectural government pouring 40 billion yen a year into building and maintaining their infrastructure.
Sources close to the FTC said similar bid-rigging is also suspected to have been committed for public works ordered by municipal governments, prompting suspicions that such practices existed for a long period of time.
In May and June, executives of local construction firms and the then mayor of Shikamachi, Nagasaki Prefecture, were arrested on suspicion of bid-rigging and bribery over a fishery port project ordered by the town.
Penta-Ocean and Wakachiku are both major construction companies based in Tokyo and listed on the Tokyo Stock Exchange's first section. They are strong in waterfront civil engineering projects.