Australian Associated Press quoted the captain of the Australian naval ship HMAS Kanimbla, Commander George McGuire, as saying nine of the 11 people aboard the Sea King helicopter died when it crashed on approach to a village on the remote west coast of Nias island.

McGuire said two on board the helicopter survived and were airlifted back to the Kanimbla for emergency surgery by the ship's second helicopter, which landed with a medical team after seeing smoke from the crash site.

"They are in a serious condition with leg fractures and other injuries," McGuire was quoted as saying by an AAP reporter on board the Kanimbla.

"We believe the rest of the personnel died," he said.

The Australian Defence Force in Canberra confirmed a helicopter from the Kanimbla had crashed but could not comment on the death toll, saying it was awaiting details of the incident.

The helicopter had been ferrying an emergency medical team from the Kanimbla to the Nias's Amandraya region as part of relief efforts following the 8.7 magnitude earthquake which ravaged Nias and nearby islands on Monday, leaving several hundred people dead.

McGuire said seven of the dead were male and two were female.

He said he had immediately ordered the Kanimbla to the site where the helicopter crashed.

"That location is a very remote location," he said, adding that the trip would take about six hours to steam to the site where the chopper, call sign "Shark 02", went down," he said.

If confirmed, it would be the deadliest incident involving the Australian military since 18 servicemen, including 15 members of the crack Special Air Service regiment, died when two Black Hawk helicopters collided during a training exercise in Queensland state in June 1996.