South Korea's producer prices fell for two straight months in May due to a decline in prices for crude oil and vegetables, the central bank said Monday.

The producer price index (PI), a barometer of future consumer price inflation, retreated 0.6 percent in May from a month earlier, according to the Bank of Korea (BOK).

The May figure was down from a 0.1 percent fall tallied in April. From a year before, the producer prices rose 1.9 percent last month, down from a 2.4 percent gain registered for the previous month.

The on-month fall was mainly attributed to falling global oil prices and a drop in vegetable prices. Dubai crude oil, South Korea's benchmark, averaged 107.32 U.S. dollars a barrel in May, down 8.5 percent from the previous month.

Manufactured goods prices dropped 0.7 percent on-month in May, down from a 0.2 percent advanced tallied in the previous month, due to falling oil prices that was passed through to the prices for petroleum and chemical products. Prices for petroleum products dropped 3.4 percent last month, with those for chemical products falling 0.8 percent.

Prices for agricultural, livestock, and fishery products dipped 1.6 percent on-month in May due to a plunge in vegetable prices that outweighed a rise in prices for fruits and livestock products. Vegetable prices plunged 11.4 percent in May from a month before, while prices for fruits and livestock goods rose 4.2 percent and 0. 5 percent respectively.

Service prices edged down 0.1 percent in May from a month earlier amid a decline in telecommunication fees and financial service charges.

Prices for electricity, water and gas dropped 0.7 percent on- month in May, down from a 0.2 percent on-month decline tallied in the previous month.