Exports in September are expected to have declined 4.0% from a year earlier, the poll of economists showed, though the pace of decline slowed from an 8.2% drop in August.
Imports are forecast to have fallen 2.8% from a year earlier, which will see the trade balance swing back to a surplus of 54 billion yen ($497.51 million) from a revised deficit of 143.5 billion yen in August.
"There was some recovery in exports of electronic parts and devices but shipments to Asia including China lacked strength," said Yusuke Shimoda, senior economist Japan Research Institute.
China's third-quarter economic growth slowed to the weakest pace in almost three decades, data showed on Friday, hit by soft factory production amid a bruising Sino-U.S. trade war and lacklustre demand at home.
The slowdown in the Chinese economy and Beijing's tense relationship with Washington have had a negative impact on Japan's exports and its trade-dependent economy. Many Japanese companies in electronic parts and semiconductors ship goods to China, where they are assembled to make final products destined for the United States and other markets.
Increasing signs of slowing global demand have made Japan's policymakers less confident about an early pick-up in global growth and more open to debating policy easing.
U.S. President Donald Trump on Oct. 11 outlined the first phase of a trade deal and suspended a threatened tariff hike, but officials on both sides said much more work needed to be done.
"There are some positive signs from the U.S.-China trade dispute and Japan's exports may stop falling," said Yoshiki Shinke, chief economist at Dai-ichi Life Research Institute.
"But we need to continue to watch closely the progress of trade talks between the two nations as trade conflicts could reignite."
The Finance Ministry will announce trade data at 8:50 a.m. Japan time on Oct. 21 (2350 GMT, Oct.20).
(Reporting by Kaori Kaneko; Editing by Jacqueline Wong)