One killed in Indonesia helicopter crash during firefighting operation

One person has died after a helicopter crashed into a river in Indonesia during a mission to fight wildfires inSouth Kalimantan.

An Indonesian crew member was killed, while two others on board - an Australian and New Zealander - were "found safe" and taken to hospital for treatment, according to Indonesia's disaster mitigation agency.

Investigations into the accident are ongoing, the agency said on Sunday, adding that it could continue its firefighting operations.

For months, parts of Indonesia have been battling wildfires that have shrouded large swathes of South East Asia in toxic haze. The blazes in forests and peatlands are fuelled by a dry season that has been exacerbated by El Niño.

Videos posted by Indonesia's disaster authorities and circulating on social media show the helicopter hovering over the river with a helicopter bucket - a collapsible container typically used to douse water over fires - before it nosedives into the water.

Other videos show rescuers later reaching the partially submerged helicopter by boat.

The deceased crew member was named by Indonesian authorities as Yayan Supyansuri. The two men rescued were Michael John Betterridge, an Australian national, and Hugh Andrew John Page, a New Zealander, according to a statement from disaster authorities.

The fallen chopper, a Super Puma H-225, was owned by a company that disaster authorities had contracted for the firefighting operations, a disaster official told AFP.

The incident comes days after another helicopter crashed in central Kalimantan during a firefighting operation, killing three crew members.

The military said on Saturday that they had managed to retrieve the helicopter's blackbox, which would help their investigations into the cause of the crash.

Despite intensive firefighting efforts, the wildfires in Indonesia this year have been especially difficult to tame due to drought conditions exacerbated by a stronger El Niño.

The raging wildfires sent toxic smog blanketing cities in Indonesia, turning the air amber and triggering a surge in respiratory illnesses in cities across the islands of Kalimantan and Sumatra.

The haze also drifted to neighbouring Malaysia and Singapore, where it has triggered public health concerns.

Foreign governments have sent assistance to help with firefighting efforts, including Australia, which has deployed aircraft and 20 personnel including pilots and paramedics.