Exports dropped for an 11th consecutive month and by 14.7% in October from a year earlier, the data showed, the biggest decline since January 2016 and worse than a 13.8% fall tipped in a Reuters survey.
But the government said the worst may be over. Trade, Industry and Energy Minister Sung Yun-mo said in a statement
that the rate of decline would begin narrowing due to solid demand in volume terms and as semiconductor prices fall less sharply.
Economists also have predicted year-on-year comparisons would start to moderate soon due to the calendar effect, unless global demand plunges further. South Korean exports started falling in November last year.
"Average exports per working day remains high and some of the (global) uncertainties are clearing. So, I expect the rate of decline to narrow and it will turn positive early next year," said Park Sang-hyun, chief economist at Hi Investment & Securities.
Investors largely shrugged off the poor October data while focusing on the latest twists and turns in US-China trade talks and on a positive private business survey on China's manufacturing sector, also released on Friday.
The benchmark stock index KOSPI slightly extended gains, while the won slightly cut losses. Three-year treasury bond futures pared gains.
Leading the poor showing in October were a plunge of 32.1% in semiconductor exports in value as prices tumbled from last year's super rally and a 16.9% fall in total shipments to China, also down from a boom at that time.
Semiconductors, including memory chips made by global giants Samsung Electronics and SK Hynix, account for 18% of South Korea's total exports, while China takes in 25% of its neighbour's global shipments.
The government now expects semiconductor prices to begin improving from late this year on solid demand worldwide.
Park Tae-sung, deputy minister for trade and investment at the ministry, told a news conference that chip exports could recover soon, saying global buyers' inventories had nearly returned to normal levels and that prices of some memory chips had turned around.
He also said many of the new ship orders received by local companies during a boom in 2017 were due for delivery from early next year. Ships are another major South Korean export.
Imports in October slid 14.6% from a year earlier, more than a predicted 13.2% drop in the Reuters survey. That brought the October trade balance to a $5.39 billion surplus, versus a $5.98 billion surplus in September.