Four asylum seekers are missing after climbing aboard a raft made of inner tubes and bamboo sticks and casting themselves adrift from a boat north of Christmas Island.
On January 25 the HMAS Leeuwin intercepted a boat drifting 17.5 nautical miles (32.4km) north of Christmas Island, Australian Maritime Safety Authority spokesman Richard Wallace said.
They believe that 24 hours earlier four people left the boat on a makeshift raft made of inner tubes and bamboo sticks tied together with rope.
The raft was last seen heading south towards Christmas Island.
The search for the four people, coordinated by the Australian Maritime Safety Authority, enters its fourth day today.
Aside from a bamboo paddle sighted on day two of the search, no sightings have occurred, Mr Wallace said.
RAAF planes and the HMAS Leeuwin have been deployed in the search, and merchant vessels have been asked to travel through the area on the lookout for the stricken raft.
Search operations will be reviewed at the end of the day, Mr Wallace said.