Australia has confirmed it handed over a boatload of asylum seekers to Sri Lankan authorities in a transfer at sea, drawing outrage from rights groups who fear those on board could face persecution when they go home.

The 41 Sri Lankans were intercepted by Australia's border patrol off the Cocos Islands in the Indian Ocean in late June, Australian immigration minister, Scott Morrison, said in a statement on Monday.

"All were screened in terms of any potential protection obligation and none were found to be owed that protection.

Immigration Minister Scott Morrison

This is the first time Prime Minister Tony Abbott's government has confirmed that it has screened asylum seekers at sea and returned them directly to their home country.

On Sunday, the asylum seekers were handed over to the Sri Lankan government after their refugee claims were assessed at sea and rejected.

For days, Morrison refused to comment on reports that Australian officials had intercepted two boats carrying around 200 Sri Lankan asylum seekers and handed them over to Sri Lankan authorities.

On Monday, the minister again declined to say whether a second boat exists, and his spokesman did not respond to requests for clarification.

In a bid to stem a rising tide of asylum seekers trying to reach Australian shores, the conservative government implemented a tough policy of turning back their boats.

Until now, vessels had been returned to Indonesia, where asylum seekers from Afghanistan, Iran, Sri Lanka, and other countries pay people smugglers to ferry them to Australia aboard rickety boats.

Among the asylum seekers leaving Sri Lanka are ethnic Tamils who survived a lengthy civil war between government troops and the now-defeated separatist Tamil Tiger rebels.

Refugee advocates say Tamils still face violence by the military.

"Some of these people will be handed straight back to danger," said Sarah Hanson-Young, immigration spokeswoman for the minor Greens party.

'Profound concern'

Morrison said four of the asylum seekers on board were Tamils, and said none were at risk of persecution.

"All were screened in terms of any potential protection obligation and none were found to be owed that protection," Morrison told Macquarie Radio.

The initial reports of a handover last week prompted the United Nations Refugee Agency, UNHCR, to issue a statement expressing "profound concern" that Australia was processing asylum seekers at sea rather than bringing them ashore to assess their claims.

"International law prescribes that no individual can be returned involuntarily to a country in which he or she has a well-founded fear of persecution," UNHCR said.

Morrison, however, said Australia had complied with its legal obligations.

Just one of the 41 people on board was assessed as possibly having a case for asylum, and was given the option of being transferred to Australia's detention camps in the South Pacific island nations of Nauru or Papua New Guinea for further processing, Morrison said.

The asylum seeker opted instead to return to Sri Lanka.

Source: Al Jazeera and agencies