Obayashi Corp., one of the country's four largest general contractors, said Tuesday that its president, Toru Shiraishi, will step down in a bid to shake up management as the firm faces allegations of bid-rigging involving construction related to the ¥9 trillion maglev rail project.

Shiraishi, 70, will step down on March 1 and be demoted to a director. Managing director Kenji Hasuwa, 64, will replace him at the head of the construction giant.

It was also announced that representative executive vice president Kozaburo Tsuchiya, 66, who leads the firm's civil engineering department, resigned from that post Tuesday. Tsuchiya will become a contract worker starting Wednesday, Obayashi said.