An inter-island ferry carrying more than 700 passengers and crew caught fire as it neared port on the island of Borneo, an Indonesian television channel reported.
District chief Wahyudi Anwar told MetroTV that rescuers pulled 10 survivors from a river outside the town of Sampit, around 500 miles north-east of Jakarta.
The status of the other passengers was not immediately clear, but attempts were being made to evacuate others, the broadcaster said.
Mr Anwar said the vessel, the KM Dharma Kencana, was travelling from Surabaya, the provincial capital of East Java, to Sampit, a district town in Central Kalimantan, with 706 passengers and 22 crew.
Boats are a main source of transportation in Indonesia, a vast archipelago with more than 17,000 islands.
Overcrowding and poorly enforced safety standards cause frequent accidents.