A naval vessel has plucked 77 asylum-seekers to safety after their boat broke up on the way to Australia.

The boat was spotted by an Australian border protection plane on a routine patrol 60 nautical miles north of Ashmore Island in the Indian Ocean, with a number of people in the water.

Three more aircraft, three merchant vessels and Australian navy ship HMAS Childers were dispatched to the scene, the Australian Maritime Safety Authority (AMSA) said.

"A short time later, the crew of HMAS Childers reported to have recovered 77 people from the water," the AMSA said, adding that an aerial search found no one else.

"Following interviews with the survivors, the crew of HMAS Childers is confident to have rescued all the people on board the vessel when it broke up."

An AMSA spokeswoman said no distress call was received and it had no information of the nationalities of the survivors.

"We have limited information at the moment. We don't know what caused the boat to break up but bad weather could have been a factor."

Australia is facing a steady influx of asylum-seekers arriving by boat, many of whom use Indonesia as a transit hub, paying people-smugglers for passage on leaky wooden vessels after fleeing their home countries.

Hundreds have died making the treacherous journey over the past few years.

The AMSA said survivors of the latest sinking were being taken to the remote Australian territory of Christmas Island for processing.