The UNHCR has expressed “profound concern” that two boats carrying Tamil asylum seekers may have been sent back to Sri Lanka by the Australian government, and directly raised the possibility that Australia has broken international law.



In a statement issued on Thursday evening, the UNHCR’s regional office in Canberra said it had received no official confirmation from the government that the two boats were being turned back, but said: “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.



“When boats presumed to be carrying asylum seekers are intercepted, UNHCR’s position is that requests for international protection should be considered within the territory of the intercepting state, consistent with fundamental refugee protection principles.”



The Australian prime minister, Tony Abbott, and the immigration minister, Scott Morrison, have refused to confirm either boat’s existence under a tight veil of secrecy imposed under Australia’s hardline military-led border regime. But both said all action taken by the Australian government was consistent with its international obligations, a claim fervently contested by human rights groups and opposition politicians.

Numerous reports since Friday documenting the existence of both boats – one of which departed from Tamil Nadu, southern India – have suggested that those on board are being transported to Sri Lanka with the co-operation of the Sri Lankan navy, an action the Australian Greens leader, Christine Milne, described as “sending the persecuted back to the persecutors”.



On Thursday Abbott described Sri Lanka as “not everyone's idea of an ideal society” but one that was “at peace”. The Rajapaksa government in Sri Lanka is being investigated by the UN Human Rights Council for alleged war crimes committed during the 2009 civil war.



On Wednesday it was revealed that asylum seekers on at least one of the boats were subjected to a rapid process on board an Australian customs vessel, in which their claims for asylum were screened in short interviews by teleconference. Those “screened out” have no right to launch a claim for protection; anyone “screened in” faces transfer to an offshore detention centre and would have no legal right to settle in Australia.

Guardian Australia revealed that in 2012 the Australian government was told that screening asylum seekers’ claims on board Australian vessels was not lawful.



On Thursday the UNHCR raised particular concerns that the asylum seekers on board had not been adequately screened.



“UNHCR considers that individuals who seek asylum must be properly and individually screened for protection needs, in a process which they understand and in which they are able to explain their needs,” it said.



“Anything short of such a screening, referral and assessment may risk putting already vulnerable individuals at grave risk of danger.”



In a near-farcical media conference on Thursday, Morrison repeatedly refused to comment on the boats and said he had not been contacted by the UN over the incident – a statement that now appears at odds with the contents of the UNHCR release.

The Australian government has been accused of failing to allow either asylum-seeker boat to arrive in Australia in order to keep its election promise to “stop the boats”. Both Abbott and Morrison regularly hold media conferences to mark incremental periods on the time that has passed without an asylum-seeker boat arrival.

The Australian Greens immigration spokeswoman, Sarah Hanson-Young, said the UNHCR comments were “highly significant”.



“It is clear that the international community is extremely concerned with the Australian government’s attitude toward asylum seekers,” Hanson-Young said.



“This secret boats policy is becoming an international disgrace.”

