Data from the Korea Customs Service suggests the country's exports are on course to fall for an eighth month in a row.
In the first 20 days of July they were down 14 percent.
The decline was led by semiconductors, which account for almost a fifth of South Korea's total exports, were down 30 percent and petrochemical goods were down more than 15 percent.
Overall exports to China and the EU fell by double digits, and exports to the U.S. dropped five percent.
In July, semiconductors are on course for an even bigger on-year decline than in June when chip exports fell 25 percent.