Tony Abbott has defended his government's secrecy over its treatment of asylum seekers, saying he would not give information that would help a war enemy.

"If stopping the boats means being criticised because I'm not giving information that would be of use to people smugglers, so be it," Mr Abbott told Network Ten on Friday.

"If we were at war we wouldn't be giving out information that is of use to the enemy just because we might have an idle curiosity about it ourselves".

The Prime Minister said the bigger goal - stopping the boats - appeared to be working, and his claim is supported by new figures that show not a single asylum seeker has been taken into immigration detention for more than three weeks.

This appears to confirm reports that navy personnel have towed or turned back at least one asylum boat towards Indonesia during the same period.

The Immigration Minister has brought an end to weekly briefings on the progress of the government's strategy for stopping asylum seeker boats - Operation Sovereign Borders - and instead issued a statement on Friday afternoon.

It shows that during the past week, 59 asylum seekers have been transferred to offshore detention centres on Manus Island and Nauru. Since the Coalition began its military-led "Operation Sovereign Borders" policy on September 18, 133 asylum seekers have decided to leave detention and return home.

Opposition Leader Bill Shorten rejected Mr Abbott's war justification. "The Abbott government is now engaging in hiding the truth," he said on Friday. "They prefer a secret to being straight with people."

Neither the Prime Minister nor Scott Morrison will confirm reports that navy personnel intercepted the boats and towed them on the high seas for five or six days back towards West Papua.

But journalists have seen film footage and taken statements from multiple sources that reveal at least one asylum seeker boat has been intercepted during the past fortnight. The fact that these asylum seekers never arrived on the Australian mainland lends further weight to the reports.

One group of asylum seekers claimed they were intercepted near Darwin on January 1 and towed for six days before being dumped outside Indonesian waters. Some said they were physically mistreated by Australian defence personnel.

The Chief of Australia's Defence Force David Hurley avoided confirming the tow back occurred, but rejected the claims of mistreatment, saying his men and women "consistently demonstrate great compassion and courage, often at great risk to their own safety".

Mr Morrison also defended the navy personnel, though he refused to confirm or deny any details of their "on water" operations.

Defence personnel "conduct their roles with the highest levels of professionalism, integrity and personal courage in extremely trying and challenging circumstances," Mr Morrison said in a statement.

"Actions and activities are undertaken consistent with Australian domestic law and Australia's obligations under international law."

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