The data released Tuesday by the Ministry of Economy, Trade and Industrial add to pressures on the central bank to stimulate the economy.
The economic recovery that followed Japan's March 2011 disasters has been doused by slowing global growth. Flaring tensions with China over disputed islands in the East China Sea have further crimped demand, especially for big-ticket items like cars. Slowing growth in China, meanwhile, has hit demand for industrial inputs like steel and machinery.
"Industrial production is on a downward trend," the ministry said, forecasting a further decline in October, followed by a rebound in November.
Exports, usually a bright spot for Japan's economy have also been sapped by the prolonged crisis in Europe and the persistent strength of the yen, which makes products made in Japan relatively more expensive in overseas markets.
Shipments of passenger cars dropped 12.6 percent in September from August and 13.2 percent from a year earlier, METI reported. Shipments of virtually all other products also fell.
Jobless rate figures for September likewise offered little encouragement, as the government reported the seasonally adjusted unemployment rate was 4.2 percent in September, unchanged from August.
The ratio of job offers to seekers fell to 0.81 from 0.83 in August, meaning there were 81 jobs for every 100 job seekers.
The central bank was meeting Tuesday, with many expecting it to expand its assets-purchasing program, aimed at catalyzing demand to counter slowing growth.
(Copyright 2012 by The Associated Press. All Rights Reserved.)