The Supreme Court ruled Thursday that it is unreasonable for Japan Post Co. not to provide its fixed-term employees with the same allowances it pays to regular workers.
The top court's judgment in favor of nonregular workers came two days after it ruled against them in two other cases over a law that prohibits unreasonable gaps between the treatment of such employees and regular workers.
The court's No. 1 Petty Bench, presided over by Justice Atsushi Yamaguchi, addressed allowances widely paid in Japan to employees whose family members are financially dependent on them as well as extra pay for work during the year-end and New Year's holidays — the busiest season for the mail service due to greeting-card delivery.
The court said it was "illegal" not to include the plaintiffs in the additional payroll, as they had been working at the company long-term through repeatedly renewed contracts.
Nearly half of the approximately 390,000 employees at Japan Post are nonregular workers. The ruling is expected to put pressure on the firm to dramatically revise its working conditions.
"We will swiftly conduct labor negotiations following the ruling and work on reforming the system in light of the issue's importance," Japan Post said in a statement.
A total of 12 nonregular employees, including two who have since retired, had filed three lawsuits in 2014 in Tokyo, Osaka, and Saga, leading to different high court rulings in the respective regions.
After the law prohibiting unreasonable gaps in treatment between fixed-term and indefinite-term employees took effect in 2013, the government set a policy of equal pay for equal work, but critics say the extent to which it prevents different treatment is unclear.
The employees, who have worked at post offices in six prefectures as well as the capital, also took issue with their employer for denying them to summer and winter holidays and sick leave.
Saga District Court sided with the firm but, in a subsequent appeal, Fukuoka High Court ruled that the lack of summer and winter holidays was unlawful, ordering the company to pay the nonregular worker about ¥60,000 ($570) in compensation. Japan Post appealed the high court ruling at the Supreme Court, but the appeal was rejected.
On Tuesday, in the two separate cases, the top court rejected the provision of bonus and retirement payments to nonregular employees of Osaka Medical College and Metro Commerce, a subsidiary of Tokyo Metro Co., which runs the capital's subway system.
The Supreme Court had said in June 2018 that whether different treatment is unreasonable should be judged not only by the total pay but by the purpose of each item making up pay and allowances.