Amid concerns Australia is breaching international refugee obligations, Prime Minister Tony Abbott is refusing to disclose what is happening at sea.
"All too often information has been given out in the past which has aided and abetted people smugglers," he told reporters in Melbourne today.
There are reports asylum seekers are being secretly screened at sea via video link, with some hopeful refugees to be transferred into Sri Lankan custody at sea after being asked four basic questions.
It followed speculation that a boatload of Tamil asylum seekers was handed over to the Sri Lanka Navy.
Abbott said divulging details of sea operations would act as "an advertisement for people smuggling".
"One of the tragedies of the six years prior to September was that the red carpet was laid out for people smugglers and their customers," he said.
"We've rolled up that red carpet."
Abbott said he was confident the actions of Australian personnel were consistent with safety at sea and international obligations.
He said Sri Lanka was not "everyone's idea of the ideal society", but was a country of peace and no longer plagued by civil war.
Australian Greens leader Christine Milne disputed this, saying kidnap, torture and rape were frequent in Sri Lanka and Australia's decision to expose asylum seekers to such risks was wrong.
Labor accused the government of "throwing out the human rights handbook", while the Human Rights Law Centre has asked the UN to stop asylum seekers being handed over to Sri Lankan authorities.
Abbott said the government reserved the right to turn around asylum seeker boats where it was safe to do so, insisting Australia's border protection policy adhered to international law.
"I would be very happy to give the Australian people an assurance that we are absolutely confident that no harm would come to anyone who has been in our charge," he said.