The death toll in the wildfires raging across South Korea's southeastern region rose to 24 and the pilot of a firefighting helicopter was killed when the aircraft crashed on Wednesday, as the country battles some of its worst forest fires in decades.

Deadly wildfires have burnt across South Korea's southeast since last weekend, claiming the lives of at least 28 people and displacing nearly 40,000.

At least 27 people were confirmed dead, including a pilot of a firefighting helicopter which crashed yesterday. Hundreds of structures have been burnt or damaged, including historic 7th-century Buddhist temple that was reduced to ashes as the fire continued to expand.