South Korea's import prices declined for the 11th straight month in July as the local currency's gain helped offset higher oil costs, the central bank said Monday.

In local currency terms, the country's import prices declined 4.3 percent in July from a year earlier after falling at the same pace of 4.3 percent in June, according to the Bank of Korea (BOK).

The import prices have fallen every month since September last year when such prices dipped 2.2 percent on-year. In March, the import prices fell 10.8 percent from a year ago, the steepest fall in 41 months.

Prices of Dubai crude, South Korea's benchmark, rose 4.5 percent in July from a year earlier, compared with a 6.1 percent on-year gain in June. The local currency gained 1.43 percent to the U.S. dollar in July compared with a year ago.

But compared with a month earlier, the import prices inched down 0.8 percent in July after rising 2.1 percent on-month in June.

Meanwhile in local currency terms, South Korea's export prices fell 1.5 percent on-year in July following a 2 percent on-year decline in June.

The export prices edged down 0.8 percent in July from the previous month, compared with a 2.6 percent on-month gain in June, according to the central bank.

The BOK said that prices of petrochemical products rose on higher oil costs, but export prices of metal products and mobile devices declined. (Yonhap News)