Grave concerns are held for the crew of a fishing vessel in the southern Indian Ocean near Antarctica, the Australian Maritime Safety Authority (AMSA) says, with rescue planes unable to find it after it set off an emergency distress beacon.

One of the Royal Australian Air Force (RAAF) P3 Orions involved in the search for missing Malaysia Airlines flight MH370 was diverted late on Sunday to locate the 75-metre Tanzanian-flagged fishing support vessel.

AMSA says it located the signal of the emergency beacon, activated earlier on Sunday, more than 3,200 kilometres south-west of Perth.

"The vessel was not located but debris was seen in the location of the beacon signal," AMSA said in a statement.

"Grave concerns are held for the crew."

AMSA has been unable to make contact with the boat and says the nature of the distress is not known.

The search for the fishing vessel will continue today subject to weather conditions.

AMSA is also trying to identify and contact the owners of the vessel to help determine exactly where it is.

A civilian jet has been sent to replace the Orion in the MH370 search, which on Sunday saw eight ships and nine aircraft scour a massive area in the Indian Ocean west of Perth.