The latest lifeboat provided to return asylum seekers safely back to Indonesia's shores has arrived leaking, after hitting coral and rocks, naval officers say.
The Abbott government has spent $2.5 million on a number of the disposable life boats to send asylum seekers back to Indonesia as part of its border control policy.
Operation Sovereign Borders commander Lieutenant General Angus Campbell on Tuesday wouldn't say what, if any, arrangements were in place to retrieve the lifeboats once they land in Indonesia.
Customs and Border Protection chief Mike Pezzullo told a Senate estimates hearing the orange vessels were "highly survivable," rather than "unsinkable".
One of the boats came ashore at Central Java's Karangjambe Beach, a coral beach, about 1pm (1700 AEDT) on Monday, with 26 men aboard.
Staff from the Indonesian naval post at Logending Beach say it arrived damaged.
"At first we wanted to move it," spokesman Suarto said.
"But then, it was impossible because it's already leaking, maybe it hit rock or something."
Another officer, Naswan, said the boat had also been looted of its equipment - life vests, ropes and TV - before the authorities found it.
Cilacap immigration office chief Imam Prawira said the boat's all-male passengers - nine Iraqis, six Pakistanis, four Nepalese, one Bangladeshi, five Egyptian and one Iranian - would be detained.
"It's said that they were rejected by the Australian government and then they were given and put inside the lifeboat so that they would leave Australian water territory," he said.
One of the men, Zuhid Ali, from Pakistan, told immigration officers they were sent back three days ago, he said.
The UNHCR, International Organisation for Migration and the relevant embassies had been informed, while the boat had been secured at the naval post.
Australian officials won't confirm reports that 10 or 11 lifeboats have been purchased, citing concerns it would give too much information to people smugglers.
The boats were supposedly designed in a way to avoid sabotage by asylum seekers and ensure they make it back to Indonesia.