Overseas sales in September were seen growing 16.3% from a year ago, the median forecast in a poll of 22 economists showed, although down from a 34.8% expansion recorded in August.
Most economists mainly attributed the slower growth to two fewer working days due to the Korean thanksgiving Chuseok holiday, but they expected per-day exports to remain strong.
"We expect headline export growth to stabilise largely on the Chuseok holiday in September, but underlying momentum to remain resilient following the trend in 20-day export data," said Kathleen Oh of BofA Securities.
"We expect external demand to remain solid across regions and products including semiconductors and non-tech products," she added.
Data from last week showed exports for the first 20 days of the month jumped 22.9% year-on-year, with those of semiconductors, petroleum products and wireless devices soaring 7.7%, 95% and 19.6%, respectively.
Exports to the country's main trading partners during the same period remained strong, with those to China, United States and European Union surging 19.7%, 24.9% and 34.2%, respectively.
Wednesday's poll also forecast South Korea's total imports to have risen 27.0% year-on-year. That compares with 44.0% in August, the fastest growth since May 2010.
"As the import growth rate is higher (than export growth), the Korean economy is expected to show the possibility of improvement in domestic demand and exports together," said An Ki-tae, economist at NH Securities.
The full month trade data will be released on Friday at 9 a.m. local time (0000 GMT).
In the same poll, 10 economists separately predicted that consumer prices this month would rise 2.3% from a year earlier, down from a 2.6% increase logged in August but staying above the central bank's 2%-target for a sixth straight month.
Some 19 economists also estimated that industrial output in August would have grew a median 0.5% month-on-month.
(Reporting by Joori Roh; additional reporting by Jihoon Lee and Bangalore polling team; editing by Richard Pullin)
