Japan's exports to China dropped sharply in September, hit by the row over the Diaoyu Islands, adding to market concerns about the outlook for the world's third-largest economy in the fourth quarter.

Workers oversee a container being loaded onto a truck at a port in Tokyo. Japan's exports fell the most since last year's earthquake as the global slowdown, the yen's strength and a dispute with China increase the odds of a contraction in the world's third-largest economy. [Photo: China Daily]

The total volume of Japan's exports fell 10.28 percent year-on-year in September, which was the largest decline since the aftermath of the 2011 earthquake, leaving a deficit of 558.6 billion yen ($7 billion), according to data released on Monday by Japan's Finance Ministry.

This is Japan's third consecutive monthly deficit.

Its export volume has shrunk for four consecutive months since June as demand decreased amid weak global growth.

The year-on-year drop was 5.79 percent in August and 8.11 percent in July.

Japan's exports to China fell 14.1 percent year-on-year in September, the fourth consecutive monthly fall. The decline has accelerated from 9.9 percent in August and 11.9 percent in July, according to official Japanese data.

"The significant contraction in Japan's exports was absolutely influenced by strained relations with China since September," said Yao Haitian, a researcher at the Institute of Japanese Studies at the Chinese Academy of Social Sciences.

The gloomy export outlook may add to the problems faced by the world's third-largest economy, which could push the Japanese government to take more measures to stabilize growth, Yao said.

According to a report from JPMorgan, the row between Japan and China is expected to drag Japan's gross domestic product down by 0.8 percentage points in the fourth quarter.