A boat carrying about 200 people has capsized north of Christmas Island, Australian officials say.
The Australia Maritime Safety Authority (AMSA) said the boat sank in Indonesian waters, 120 nautical miles (220km) north of the island.
Survivors had been spotted in the water, AMSA said.
Three merchant vessels and two Australian patrol boats were being sent to the area to help, AMSA said.
Christmas Island lies off Australia's north-west coast. Boats from Indonesia carrying asylum-seekers who want to go to Australia often make for Christmas Island.
About 50 asylum seekers died when their boat broke up on rocks off Christmas Island in December 2010.
"The Indonesian search and rescue authorities are coordinating the response," an official from the AMSA was quoted by news agency Agence-France Presse as saying.
"We can confirm there are survivors but we can't confirm numbers at this stage."