The death toll from the sinking of an Australia-bound asylum-seeker boat off Indonesia has risen to 36, an official said, as Australia's new Prime Minister Tony Abbott is set to begin a visit to Jakarta.

The boat, which was estimated to be carrying between 80 and 120 asylum seekers, went down on Friday in rough seas off Indonesia's main island of Java.

Twenty-eight people escaped alive as the boat foundered but more are still believed to be missing.

Search teams found "four more bodies this morning, two of them are children," Warsono, police chief in the Agrabinta area of Java, where the boat went down, told the AFP news agency on Monday.

The official said this was on top of 11 bodies discovered on Sunday as the search teams scoured the coast. The total death toll was now 36, he said.

'Sovereign Borders'

Rescuers have been unable to deploy boats to hunt in the rough seas, with waves at heights of four to six metres.

Abbott is due to arrive in Jakarta later on Monday to kick off a two-day visit, his first overseas trip since becoming premier, where his tough refugee policies are expected to be the focus of discussions.

He has put in place a military-led operation known as Sovereign Borders, which involves turning boats around when it is safe to do so, as he seeks to stem the flow of asylum seekers arriving in Australia.

Hundreds have died in recent years attempting the journey after boarding rickety, wooden boats in Indonesia.

But just a few weeks after winning power, Abbott's new government is facing criticism over Friday's accident after survivors claimed their calls for help to Australian rescuers went unheeded.

Australian Finance Minister Mathias Cormann insisted at the weekend that Australia had provided "all appropriate assistance".

Source: AFP