Workers put in an average of 141.9 hours in January, up 1.3 percent from a year earlier for the first year-on-year rise in three months.
The Health, Labor and Welfare Ministry said Monday that average overtime hours rose for the 19th month in a row, and scheduled working hours increased for the first time in three months, up 1.1 percent to 132 hours.
On the wage front, the average scheduled cash earnings edged up 0.3 percent from the year before to 258,662 yen for the first increase in four months, and nonscheduled pay rose for the 18th consecutive month, according to the preliminary report covering companies with five or more employees.
But the overall average monthly wage slipped 0.8 percent to 291,574 yen, marking the second straight month of a year-on-year decline, it said.
The ministry attributed the slide in the entire cash earnings to growing moves by businesses to use more part-timers.
The number of workers on regular payrolls inched down 0.2 percent in the reporting month to 42.77 million. The number of full-time workers fell 0.5 percent, while part timers grew 1.2 percent.