Dockworkers staged a 24-hour nationwide strike Mar. 12, halting nearly all loading and unloading operations as they protested U.S. pressure to open up Japanese port services to greater competition.

The United States plans to impose sanctions over cargo-handling labor practices at Japanese ports. The strike, the first nationwide port walkout since 1985 when dockworkers picketed for higher wages, involved nearly half of Japan's 100,000 harbor workers and affected some 50 ports, including Tokyo, Yokohama and Kobe.

The Transport Ministry said that as of 1 p.m., loading and unloading work on 242 ships, 164 of them on international routes, were affected at 31 ports including the nation's six major ports. The dockworkers are also seeking better working conditions in this year's annual spring wage negotiations. Workers also plan to quit working on Sundays beginning this weekend.

The 44,000-member National Council of Dockworkers Unions of Japan and the 3,000-member Japanese Confederation of Port and Transport Workers Unions sponsored the strike. The unions said they also went on strike to protest deregulation of shipping services, saying it would undermine their working conditions.

The commission said it would impose $100,000 levies from April 14 on three Japanese shipping companies that operate in U.S. ports: Kawasaki Kisen Kaisha Ltd., Mitsui O.S.K. Lines Ltd. and Nippon Yusen K.K. With those companies' cargo vessels averaging 34 arrivals a month in U.S. ports, the agency estimated that the new levies could total $45 million a year.

The FMC complained about Japan's long-standing practice of holding "prior consultations" between shipping companies and the labor unions of cargo-handling companies, using the Japan Harbor Transportation Association as an intermediary, to decide which companies will handle container freight.