Japan's labor ministry says that employees at nearly half of the businesses inspected by its staff have been required to work illegally long hours.
The ministry conducted on-site inspections at 25,676 business establishments across the country for one year through March. They included entities where deaths from overwork have been reported.
Officials found that employees at 45.1 percent of the places they inspected had to work illegally long hours, beyond the limits set by labor-management agreements.
At 74 percent of these places, employees worked more than 80 hours of overtime per month. Health risks are believed to rise if overtime tops this figure.
Officials say one of the worst cases was 310 hours of monthly overtime.
A new law enacted by the Diet in June will cap overtime with punishment. It will take effect at large firms in April next year, and at small and medium-sized firms one year later.