Import prices in won terms dropped 17.1 percent in March compared to a year earlier, the Bank of Korea said, moderately slowing from a 17.8 percent drop in February.
Prices for intermediate goods and raw materials which have the heaviest weightings on the index, fell 10.8 percent and 33.2 percent in March on-year, respectively, attributing to the fall.
Import prices are seen as a gauge for future inflation, which is expected to remain low through the rest of the year according to the Bank of Korea. The central bank forecast last week that annual inflation would stand at 0.9 percent in 2015, which would be the lowest since 1999.
On monthly terms, import prices rose 0.4 percent last month from February, gaining for a second straight month.
The same central bank data showed export prices, also in won terms, fell 6.8 percent in March from a year ago. They fell at the slowest pace since December last year.