Indonesian fishermen have found another survivor from last Friday's disaster in which some 374 people trying to reach Australia drowned in the Java sea, the International Organisation for Migration said yesterday.

The news came as senior UN officials in Indonesia called on the government to investigate allegations that police had forced asylum seekers on to an unseaworthy boat that sank.

Achmad Hussein Ali, an Iraqi, said about 30 police officers, armed with pistols and automatic weapons, made the 418 passengers board the vessel, even though several did not want to after seeing its poor condition. He claimed the ship was escorted into international waters by policemen using their own boats.

The accusation is vehemently denied by Indonesia, which has announced that it will hold a regional meeting on the escalating refugee crisis.

An IOM official, Jose Remigio, said the Surya Terang fishing boat picked up another survivor, Sabah Latif Ali, on Monday morning.

"He had obviously been separated from the rest of the people and so was not rescued with the others," Mr Remigio said. "They saw him floating in the sea and took him in."

Mr Ali, whose age and nationality are not yet known, lost his wife and daughter in the tragedy. He and the 44 other survivors are being treated at a holding centre 20 miles south of Jakarta.

The IOM's Indonesia director, Richard Danziger, said he was trying to find alternative accommodation for the survivors, most of whom are Iraqi. The others are Afghan, Palestinian and Algerian.

The Indonesian foreign minister, Hassan Wirajuda, said yesterday that the Indonesian government would like to hold an international conference on how to tackle the growing crisis of thousands of illegal immigrants from the Middle East and Afghanistan risking their lives to reach Australia.

The UN High Commissioner for Refugees said yesterday that about 30 people who had already qualified as refugees may have been on the boat.

Speaking on Australian radio, the Australian immigration minister, Philip Ruddock, said Canberra had identified an Egyptian people smuggler operating out of Jakarta as responsible for the ill-fated boat journey.

He said Australia had informed Jakarta several times that the man was a people-smuggler. "We know who the person was who arranged this particular package of travellers and he put 400 people on a boat 10 metres long that could only take 150 people," Mr Ruddock said.

"We have offered Indonesia to accept by way of extradition all of the people-smugglers and to try them."