The price of a single cabbage hit 9,337 won (US$ 7.02) on Thursday -- up 69.1 percent from the same day a year ago, according to data released by the state-run Korea Agro-Fisheries & Food Trade Corporation.

Cabbage is a key ingredient of kimchi, the country's famed fiery fermented dish which many Koreans eat every day.

Experts say rising summer temperatures are leading to supply instability -- especially for highland cabbage, which thrives in cooler climates.

"Additionally, climate change has changed the patterns of soil disease outbreaks," said Lee Young-gyu, a virologist at the National Institute of Crop Science.

"For instance, soil-borne fungal diseases like root rot, which causes wilting in cabbage, are spreading," he told AFP.

Lee said there have also been reports of seedlings perishing from the extreme heat, or being scorched by the intense sunlight.

This month, South Korea's Rural Development Administration established a dedicated research institute to address the supply instability of highland cabbage.

The body has warned that if no measures are taken to address climate change, suitable areas for summer cabbage cultivation could vanish by 2090.

This year South Korea experienced its highest average summertime temperature since such records began half a century ago -- nearly two degrees higher than the historic average, the weather agency said earlier this month.