Mr Morrison's office cited operational matters for his silence.



Senior Indonesian sources have told the ABC that a large orange lifeboat was discovered off the south coast of central Java.



Local media reported that about 26 asylum seekers were on board, but it was unclear whether that figure also included the boat's Indonesian crew.



The unsinkable lifeboats were bought by the Australian government as part of Operation Sovereign Borders, but it has refused to confirm their use in sending asylum seekers back to Indonesia.



A spokeswoman for Mr Morrison declined to comment on the latest turn-back.



"In accordance with the Operation Sovereign Borders joint agency task force policy regarding public release of information on operational matters, the government has no further response on the issues raised," she said in a statement.



The turn-back policy has angered the Indonesians, who have rejected it as a solution to people smuggling.



Former Labor immigration minister Tony Burke criticised the government's continued secrecy.



"We get our information it seems from the Indonesian media on all of this," he told reporters in Canberra.



Australia's northern neighbour was central to tackling people smuggling, Mr Burke said.



"If anyone thinks that you can deal with this issue without a co-operative relationship with Indonesia - Indonesia's quite capable of proving that argument wrong," he said.