The high court in Australia has granted an interim injunction preventing authorities from returning 153 Tamil asylum seekers to Sri Lanka.
The decision came after Australia's government confirmed earlier that it had handed over a boatload of asylum seekers to Sri Lankan authorities in a transfer at sea.
The 41 Sri Lankans were intercepted by Australia's border patrol off the Cocos Islands in the Indian Ocean in late June, Immigration Minister Scott Morrison said.
Yesterday, they were handed over to the Sri Lankan government after their refugee claims were assessed at sea and rejected.
Politicians and human rights campaigners were outraged by the decision to return ethnic Tamils to the country and described the move as "handing them straight back to danger".
According to the Guardian Australia, however, a further bid to prevent the handover of 153 asylum seekers was succesful after a lawyer representing 48 of those on board told the court of his clients "grave concerns" that they would be handed over to the Sri Lankan military.
The injunction will hold until 4pm tomorrow afternoon.
Immigration Minister Scott Morrison early acknowledged that 41 people had been handed back to Sri Lanka, but did not comment on the fate of a second boat reportedly carrying about 150 people.
Of the 41 who were returned four of the asylum seekers on board were Tamils and none were at risk of persecution, Mr Morrison said.
"All were screened in terms of any potential protection obligation and none were found to be owed that protection," he told Macquarie Radio.
A Sri Lankan navy spokesman confirmed the asylum seekers had arrived in the southern port city of Galle, but gave no details on what would happen to them.
Generally, asylum seekers in Sri Lanka are handed over to police and face fines, but jail terms are likely only for those with proven links to militant groups or smuggling.
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.
"UNHCR considers that individuals who seek asylum must be properly and individually screened for protection needs," it said, adding that "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".
Ming Yu, spokeswoman for Amnesty International, said the cursory processing of complex refugee claims means they may not be properly investigated.
She said that could leave Australia in violation of its international obligation of non-refoulement, which forbids victims of persecution from being forced back to a place where their life or freedom is under threat.
"We know (Sri Lanka) is a country where persecution is still occurring, where torture by police is still occurring," Ms Yu said.
"So we're trying to raise the attention to the Australian government of where your actions of returning people without properly assessing their claim to asylum that you're really risking refoulement."
Mr Morrison said Australia had complied with its legal obligations.
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, he said.
The asylum seeker opted instead to return to Sri Lanka.