At least 13 people were killed when an Indonesian army helicopter crashed on Borneo island and burst into flames, a military official has said.

Rear Admiral Iskandar Sitompul said the MI-17 cargo helicopter was carrying seven soldiers and 12 civilians on a mission to build a border post near the Indonesia-Malaysia border when it went down.

He said authorities are investigating what caused the crash of the new chopper, which happened as the pilot was trying to land in remote Malinau district of North Kalimantan province.

Rescuers using a helicopter pulled 13 bodies from the debris, including five soldiers, and rushed six badly injured people to a hospital in neighbouring Tarakan town.