China's slowdown and soft domestic demand weighed on factory output and the broader economy, although the Bank of Japan saw the effects of China's slowdown as limited for now, sticking to its rosy growth outlook.
Still, weak indicators will keep the central bank under pressure to ease policy again to hit its ambitious 2 percent inflation target next year.
Some analysts expect the BOJ to move at its Oct. 30 monetary meeting, when it also issues long-term economic and price projections.
"Weak exports were within the BOJ's expectations so this data alone could not be a trigger. But there's no doubt that pressure will mount on the BOJ to act if weakness persists," said Taro Saito, senior economist at NLI Research Institute.
Separate data by the BOJ, which captures trade movements in real terms by eliminating price effects, showed real exports rose 0.2 percent in July-September while real imports grew 2.6 percent. This suggests net exports weighed on third-quarter GDP, said Yuichiro Nagai, economist at Barclays Securities Japan.