Real wages in Japan fell 0.6% in August from the prior-year period, data from the Ministry of Health, Labour and Welfare showed.
The figure followed a revised 0.5% annual increase in July.
Total cash earnings edged up 0.9% year over year in August, following a revised 1.6% annual gain in July.
Contractual cash earnings were up 1.3% year over year in August, following a 1.1% annual gain in the previous month, data showed.