Industrial production dropped a seasonally adjusted 1.2 percent on a monthly basis in June, due to flagging export growth, the Ministry of Economy, Trade and Industry said Wednesday.
The index of output at mines and factories hit 93.5 in June against the 2000 base of 100, METI said in a preliminary report.
Private-sector economists had projected a 0.4 percent increase to follow the 2.6 percent jump recorded in May.
Meanwhile, METI stated that "production is weakening," an assessment it has left unchanged for eight straight months.
The June data brought the figure for the April-June quarter to 93.4, down 0.6 point from the preceding quarter and marking the first decrease in six quarters.
In June, the fall was led by a 3.2 percent decline in transportation equipment, including automobiles, and a 1.7 percent drop in electronic parts and devices.
"Exports were not as good as expected in the reporting month," remarked METI official Kazuaki Hasegawa.