Survivors of an asylum seeker boat that sank off Indonesia say Australian rescue authorities told them help was on the way, but it never came.

The boat sank off Argabinta, a remote area of the coast off the Cianjur region of west Java, after it got into trouble in rough seas on Thursday.

More than 30 of the about 50 people either missing or dead are understood to be children.

At least 28 asylum seekers have been found alive, but local authorities fear about 80 people were on the boat.

After the sinking the beach was littered with broken pieces of the boat and the bodies of about 21 people, including many children.

Survivors say they rang the Australian rescue authorities but nobody came to help them.

Earlier police said they had found 22 people dead, but now say one of those was in a coma.

One survivor told ABC News he had lost his whole family because Australian rescuers did not come.

"We called the Australian Government for 24 hours, they were telling us 'we're coming, we're coming, we're coming,' and they didn't come," he said.

"We sent them the position on the GPS, exactly where are we, and we drowned and nobody came.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 4 minutes 34 seconds 4 m 34 s George Roberts reports from Indonesia Download 2.1 MB

"This is because of the Australian Government. I want them to know that."

Another survivor, Abdullah Al Qisi, says as the boat broke up, only those who could swim made it to the shore 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 search will being properly today.

The deputy police chief from the region said the passengers were abandoned by the skipper of their boat.

Immigration Minister confirms boat contacted Australian authorities

The Australian Government says it was aware that an asylum seeker vessel had foundered in Indonesian waters close to West Java.

A statement issued from Immigration Minister Scott Morrison's office has confirmed that Australian authorities received a phone call about the vessel.

But while survivors say they rang Australian authorities on Thursday, Mr Morrison's statement says the call was made on Friday morning.

Locals help asylum seekers who survived the deadly boat accident off the coast of western Java. ( AFP )

It says the Australian Maritime Safety Authority coordinated the initial rescue effort and notified the Indonesian search and rescue agency.

A merchant vessel responded, as well as an Australian Border Protection Command aircraft, but neither could locate the vessel.

"Australian government officials in Jakarta are seeking additional information from their Indonesian counterparts, including seeking to confirm where the vessel foundered. It is believed to have gone down in Indonesian territory," the statement says.

"Any loss of life is tragic and this latest incident again reflects the dangers of people smuggling.

"The Australian Government expresses its deepest sympathies to those affected by this tragedy for their loss and will continue to provide any assistance required by the Indonesian Government."

Australian authorities return asylum seekers to Indonesia

News of the accident broke on Friday as Australian authorities were planning to return a group of asylum seekers to Indonesia 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 was the second time in two days that Australian rescue authorities returned asylum seekers to Indonesia.

A section of the boat's hull washed up on the south coast of west Java. ( ABC News: George Roberts )

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

Acting Opposition Leader Chris Bowen said then 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.