The captain of the asylum seeker boat that sank off Indonesia late yesterday abandoned the ship, leaving the asylum seekers to find their own way to Australia, according to authorities.

At least 22 asylum seekers are dead and 30 are feared missing after the boat sank off Argabinta, a remote area of the coast off the Cianjur region of west Java.

There are reports that as many as 120 people were on the boat, and that many of those who drowned were children.

The bodies of the dead were found washing up on a beach in a local estuary, while 25 people were found there alive.

Search operations were hindered because Indonesian rescue authorities do not have the capability to search during the night or in big seas.

A large ocean swell meant rescue efforts were again delayed on Saturday morning.

The ABC's Indonesia correspondent George Roberts told Saturday AM that authorities believe the captain abandoned the ship.

"According to the deputy police chief from the region, he said that these people were abandoned by the skipper of their boat," he said.

"They were on their way Australia. The skipper left them in charge of the boat, as often happens.

"The asylum seekers effectively lost their way, lost their direction, didn't know where they were going, and they kind of went around in the dark until they ran out of fuel, then hit big waves."

The accident came as Australian authorities planned to return a group of asylum seekers today after rescuing them at sea.

The Australian Customs ship, ACV Triton, had been given permission to enter Indonesian waters to offload 31 rescued asylum seekers.

It will be the second time in two days that Australian rescue authorities have returned asylum seekers to Indonesia.

The Australian Maritime Safety Authority (AMSA) told its Indonesian equivalent Basarnas the "preference is for a transfer at sea" to Indonesian authorities.

The Coalition's new system of weekly briefings on asylum seeker issues allows for special updates when warranted, but Prime Minister Tony Abbott would not answer questions from reporters this morning.

Acting Opposition Leader Chris Bowen says the Government should not wait for its weekly briefing on asylum seekers to update the public about the latest incident.

"The Government, whether it be the Prime Minister, the Immigration Minister or the Home Affairs Minister or the Defence Minister, somebody should be providing a briefing to the Australian people today," he said.

"This can't wait for [Scott] Morrison's weekly briefing; these updates should be provided as and when the Government can."

Mr Abbott will head to Jakarta on Monday for high-level talks with the Indonesian government.