Search for more survivors called off

Authorities say up to 100 people are feared drowned after an asylum boat sank off Indonesia's coast. (AAP)

Authorities say up to 100 people are feared drowned after an asylum boat sank off Indonesia's coast. (AAP)

As tears streamed down his face, Zahir told of the nightmare he had endured after the boat he was on with about 150 others sank on its way to Australia.

Australian authorities have abandoned the search for more survivors from the latest asylum seeker boat disaster after it was determined there was no chance of anyone else being found alive.

The decision to abort the search was made as those who made it to safety revealed the harrowing ordeal they had faced as their bid to make it to Australia ended in tragedy.

Muhammed Zahir spoke on Friday of how he desperately begged for his sister to stay with him as they drifted in each other's arms for hours in the Sunda Strait, praying help would come.

But tired and injured, she couldn't hold on any longer, eventually slipping beneath the waves before the rescue boats arrived.

"She told me, 'kill yourself, let's go together'," Zahir said on Friday, just moments after arriving at the port of Merak in western Java.

"I said, 'please don't go', but she's gone."

Like the rest of those aboard the rickety wooden vessel, Zahir is an ethnic Hazara.

They were fleeing persecution in Afghanistan.

Zahir, 25, was one of 55 survivors brought to Merak in western Java on Friday. His sister, who was 29, remains one of the almost 100 others missing, feared drowned.

The survivors were brought to shore in two Indonesian search and rescue boats after earlier being transferred from larger vessels.

Among them were two women and a 10-year-old boy named Oemid.

The young boy sat quietly on the deck of the rescue boat, speaking only to say his name and reveal he had lost his father, uncle and a cousin.

They all paid at least $5000 to make the perilous journey to Australia.

It was confirmed on Friday that the people smuggler who arranged the doomed voyage is a Pakistani named Haji Ghulam.

The two groups brought ashore were taken to a hotel in Merak. They will be processed by Indonesian authorities, and placed in detention.

Unlike in other incidents in recent months involving asylum seeker boats in distress, the Australian government refused to take these survivors to Christmas Island, and insisted they be returned to Indonesia.

Prime Minister Julia Gillard said on Friday that too many people had died already making the dangerous journey from Indonesia to Australia.

More than 300 asylum seekers have died since December travelling along the same route - in the Sunda Strait between Indonesia and Christmas Island.

"It's a big ocean, it's a dangerous ocean. We've seen too many people lose their lives trying to make the journey to Australia," Ms Gillard said.

The Australian Maritime Safety Authority later announced that it had completed its assistance in the search and rescue operation, saying in a statement that there was no realistic prospect of survivability.

But Ms Gillard was forced to defend the delays in reaching those in the water during the initial search period, after questions were raised about the response from the Indonesian search and rescue agency BASARNAS.

The asylum seekers had been about eight nautical miles from Java and about 220 nautical miles from Christmas Island when Indonesian authorities were alerted to the disaster that was unfolding.

It was another seven hours before the first search teams were deployed.

By the time the first asylum seekers were rescued by a merchant vessel, they had been in the water for almost 24 hours and had drifted to a point some 40 nautical miles off the Javanese coast.

"I believe Indonesian authorities did the best that they could," Ms Gillard said.

The latest in a spate of disasters at sea comes as Indonesian and Australian officials prepare to hold talks in Jakarta next week on maritime cooperation, including enhancing collaborative efforts aimed at stemming the flow of asylum seeker boats to Australia.

Opposition immigration spokesman Scott Morrison welcomed the talks but said "the risk of further tragedies remains".