Another orange lifeboat carrying asylum seekers has turned up on the Indonesian coast after allegedly being sent there by Australian authorities, the ABC has been told.

Earlier this month ABC News obtained footage of a similar boat carrying asylum seekers being towed by an Australian Customs ship.

A senior Indonesian military source has told the ABC the latest lifeboat was discovered yesterday, about midday local time, off Kebumen, off the south coast of central Java.

Local media, including Indonesian government-owned newswire Antara, are reporting that about 26 asylum seekers were found on board, although it is unclear if that number includes Indonesian crew members.

Two passenger lists provided to the ABC contain differing numbers and an Indonesian military source says there were 24 on board.

One of the asylum seekers told Antara they nearly made it to Australia when they were sent back in the lifeboat.

It is understood they have been transferred to the nearby town of Cilacap.

The lifeboat is described as a capsule, similar to that used by Australian authorities to return asylum seekers to Indonesia on February 5 this year.

That group said they were nearly ready to disembark at Christmas Island when the Australian Navy sent them back.

The Indonesian navy said there were 34 people on board that lifeboat, which had recently been purchased by the Australian Navy.

All but two of those asylum seekers were transferred onto the lifeboat and sent back to Indonesia.

Passengers said two people resisted the Navy's attempt to put them on the lifeboat, so they were not returned to Indonesia.

Indonesian sources told the ABC at the time that those on board came from Iran, Pakistan, Bangladesh and Nepal and the youngest aboard was 18 months old.

They also said the asylum seekers were fed and medically treated by Australian authorities, but claimed to have run out of food 48 hours before landing in Java.

Labor calls for explanation of lifeboat policy

Indonesian foreign minister Marty Natalegawa has previously expressed concern over the boat turn-backs policy.

The Opposition's immigration spokesman, Richard Marles, has renewed his calls for the Government to explain how it is using the lifeboats.

"We've seen a number now being reported but the Government continues to refuse to explain what it's doing on the high seas," he said.

"This is a matter of enormous public interest in Australia. The Government needs to come clean and explain its asylum seeker policy."

The Australian Government has confirmed it has purchased lifeboats, but has not confirmed how many. Each is believed to cost at least $70,000.

A Government spokeswoman says it is not its policy to comment on operational matters.