Indonesian authorities are searching for an asylum-seeker boat that is feared to have sunk in the Sunda Strait en route to Christmas Island.
They say they received reports that more than 70 people may have been on a vessel that was believed to have sunk about midnight on Thursday but have not been able to confirm this.
A spokesperson for the Australian Maritime Safety Authority (AMSA) says a people-smuggling vessel may have sunk in or near the Sunda Strait.
She says some passengers may have been rescued by a fishing vessel.
Indonesian authorities are co-ordinating the search and rescue operation, AAP reports.
In August 2012, the authorities were criticised when more than 100 asylum seekers drowned when their boat foundered in the Sunda Strait.
An aerial search was not launched until more than six hours after a distress call was received by AMSA and it was almost 24 hours before the first survivors were pulled from the water.
Hundreds of asylum seekers have perished in recent years while making the perilous crossing from Indonesia to Christmas Island.