Jakarta – Forest fires raging in Indonesia's East Kalimantan province have killed substantial insect life, posing a problem to forest rehabilitation, the official Antara news agency reported on Sunday.

"The disappearance of insects poses a problem to the rehabilitation of burnt forests," the agency said quoting a study by Abubakar Lahji of Mulawarman University.

He conducted the study at the Bukit Suharto National Park in Samarinda, East Kalimantan and said the insect index had dropped from 30 to 5 since the fires started in January.

Animals had also fled from the conservation area due to damaged habitat and food shortages.

"It is difficult to see wild boars now because tubers which are their main food have been destroyed by the fires," he said.

The conservation area is home to a variety of endangered animals including orang-utans, bears, deer, monkeys and porcupines.

Latest estimates from the government put the devastated land area at 280,000 hectares.

On Friday, the World Wide Fund for Nature (WWF) said the scale of destruction by the forest fires was pushing orang-utans to extinction.