An underground wildfire has destroyed 40 acres of forest as it raged for 10 days in Thailand.

The fire started at the Nong Leng Sai Non-Hunting Area in northern Phayao province earlier this month.

Firefighters have been dousing the flames and creating firebreaks to prevent them from spreading.

As of April 26, more than 40 acres had been destroyed from the 400-acre forest, with many wild animals dead or displaced, authorities said.

Wararit Chaiyasan, chief of the non-hunting area, said: 'The fire has had a severe impact on the ecosystem and the livelihood of residents since it's been burning for more than 10 days.'

He added that streams in the area have been diverted to create natural firebreaks as personnel continue to battle the fire. They aim to extinguish the wildfire in two days to prevent further damage.

The Nong Leng Sai area is a natural water reservoir and a major source of freshwater in Thailand.

The Southeast Asian country has been grappling with forest fires in recent months believed to be caused by illegal agricultural burning, which locals growing crops in protected forests.