Overseas sales are forecast to surge 48.5% this month from a year earlier, the median forecast in a Reuters survey of 11 economists showed on Friday.
Such an outcome, also reflecting a low base in 2020, would mark the sharpest increase since August 1988 and extends a seventh straight month of gains. Exports grew 41.2% in April.
"Even excluding base effect, recovery in demand from advanced economies and increased trade volume will lead strong exports," said Chun Kyu-yeon, economist at Hana Financial Investment.
She said sales of chips, cars, autoparts and petroleum products are likely to have boosted exports this month.
The May 1-20 data released last week showed exports to China, the United States and the European Union soared 25.2%, 87.3% and 78.1%, respectively, while those of semiconductors, cars and petroleum products jumped 26.0%, 146.0% and 149.7%.
While the pace of shipments growth is set to slow as the base effects fade, economists remain bullish about the outlook for exports, and expect the sector to underpin Asia's fourth-largest economy as it rebounds from last year's COVID-19 led downturn.
"Export growth will gradually slow as base effect eases, but the global manufacturing boom and revenge spending trend will likely support domestic exports for the time being," said Park Sang-hyun, chief economist at HI Investment & Securities.
Wednesday's poll also forecast imports to have risen 40.5%, their strongest rate since May 2010, on higher oil and commodity prices.
Full month trade data will be released on Tuesday at 9 a.m. local time (0000 GMT).
Separately 12 economists predicted April industrial output would edge up by a seasonally adjusted 1.5% month-on-month, rebounding from a 0.8% shrink in March.
Economists also estimated consumer prices this month would rise a median 2.6% from a year earlier, the fastest since March 2012 and accelerating from a 2.3% rise in April.
(This story corrects the date in the third paragraph to August 1988, not September 1988; and in the 12th paragraph to March 2012, not December 2015)
(Reporting by Joori Roh, Jihoon Lee; Editing by Shri Navaratnam)