SEOUL South Korea's producer prices fell in June on an annual basis for the first time in 31 months, central bank data showed on Friday, dragged down by petroleum and agricultural products.

The producer price index was 0.2% lower in June than the same month the year before, after a rise of 0.5% in May, according to the Bank of Korea (BOK).

The index showed annual increases every month from December 2020 and during the streak it once hit a 14-year high of 10%.

Officials at the BOK remain cautious about whether the annual declines will continue.

"Global oil prices are rebounding this month and there will be upward pressure on agricultural products from heavy rains ... we will need to watch the trend more," a BOK official told a briefing on the data on Thursday ahead of its release.

On a monthly basis, the index fell 0.2%, its third month of declines after dropping by 0.4% and 0.1% in May and April, respectively.

Prices of coal and petroleum products were 3.7% lower than the previous month and agricultural products were 1.3% lower, but utility prices rose 1.8%.

(Reporting by Jihoon Lee; Editing by Christian Schmollinger)