South Korea's export prices fell for the first time in four months in August as the local currency appreciated against the US dollar, central bank data showed Tuesday.

The country's export price index, in terms of the local currency, dropped 0.2 percent in August from the previous month, compared with a 0.1 percent on-month gain in July, according to the preliminary data from the Bank of Korea (BOK).

The reading marked the first drop after the index rose for three straight months since May.

From a year earlier, the index sank 6.8 percent, marking the 15th straight month of on-year decline.

"Last month, the export prices declined as the won strengthened per the greenback and semiconductor prices fell," a BOK official said.

The Korean currency rose 1 percent against the dollar in August, compared with July.

South Korea's import prices declined in August from a month earlier as global demand remained tepid and prices of intermediary goods fell despite rising oil costs, the BOK said.

The country's won-based import prices index decreased 1.1 percent in August from the previous month, after posting a 0.8 percent on-month fall in July.

The index declined 10.5 percent on-year last month, representing the seventh consecutive month of on-year drop.

Prices of Dubai crude, South Korea's benchmark, rose 1.6 percent in August from the previous month. (Yonhap)