A nursing home operator in Hamura, western Tokyo, was arrested Monday on suspicion of making employees work without overtime pay in violation of the Labor Standards Law.

The arrest of Tadao Nakamura, 59, who operates the Shinmeien nursing home, marks the first time a business operator has been arrested for not paying sufficiently for overtime work.

The Ome Labor Standards Supervision Office said it was also questioning Nakamura's wife, 59, his son, 33, and a 39-year-old head of the facility's administrative office over alleged collaboration.

According to the labor watchdog office, the nursing home failed to pay about 40 care workers overtime wages for which they had been entitled starting April 1999.

Nakamura and the others allegedly manipulated the time sheets of the workers to make it appear they had not worked the extra hours. The amount of unpaid wages are estimated to total 100 million yen, according to the office.

Under the Labor Standards Law, employers cannot allow their employees to work more than 40 hours a week, except in cases where they have reached an agreement with workers. In that case, employers are required to pay 25 percent higher wages for the extra hours, and are punishable by up to six months in prison if they fail to do so.

Overtime work at Shinmeien averaged 50 hours a month per employee, with some people putting in nearly 100 extra hours, the watchdog office said.