FOUR Australians are among 10 people feared dead after their helicopter lost contact with airport authorities soon after takeoff and is believed to have crashed in eastern Indonesia.
The Bell 412 helicopter went missing over North Sulawesi province after leaving the town of Manado, search and rescue agency spokesman Gagah Prakoso said.
"We lost contact with the helicopter about 30 minutes after it took off from Manado. We suspect that it has crashed between Manado and Bitung," he said.
The aircraft left Manado around 2.30pm (1630 AEST) on Wednesday with eight passengers and two crew, Prakoso said.
"The search and rescue team has been trying to find them on land," he said.
The team called off its search after dark and will return to the area early Thursday morning.
Lieutenant Colonel Vafafe Bayu, a local police chief, told TVOne that six Indonesians and four Australians were on board the helicopter.
They apparently worked for a mining company in North Maluku.
Transport ministry spokesman Bambang Ervan said the identity of the passengers could not be confirmed.
Indonesia, a sprawling archipelagic nation of nearly 240 million, has been plagued by transportation accidents in recent years, from plane and train crashes to ferry sinkings.
Overcrowding, aging infrastructure and poor safety standards are often to blame.
Australians feared dead in chopper crash