Sri Lanka war and asylum-seekers
An internally displaced Tamil girl looks out from a broken iron grill at Konappulam Internally Displaced Persons camp in Jaffna, about 400 kilometres (250 miles) north of Colombo Reuters file photo

The 41 asylum seekers from Sri Lanka who fled the war-torn country and were eventually sent back by Australia are to face a criminal probe back home.

The immigrants, who were intercepted by authorities while attempting to illegally enter Australian territorial waters, were handed back to Sri Lanka.

The Sri Lankan navy says all the asylum seekers would be taken to the Galle port and then handed over to the Criminal Investigation Division, an intelligence wing. They are likely to face illegal immigration charges.

Of the 41 people on board the vessel, which was intercepted in the last week of June, 37 were Sinhalese and four were Sri Lankan Tamils. Only one of the Sinhalese asylum seekers passed the screening for refugees but he also chose to go back to Sri Lanka, said Australia's immigration minister Scott Morrison.

In a statement, Morrison, who is scheduled to visit Sri Lanka later this week, said: "The Australian government will continue to act in accordance with our international obligations, including applicable international conventions and to protect the safety of life at sea."

"At the same time will not allow people smugglers to try and exploit and manipulate Australia's support of these conventions as a tool to undermine Australia's strong border protection regime that is stopping the boats and the deaths at sea."

"Accordingly, the government will continue to reject the public and political advocacy of those who have sought to pressure the government into a change of policy."

He has not commented on the report suggesting that there was another boat carrying about 150 immigrants which was also headed to Australia seeking refuge.

Those who are caught and sent back while trying to flee Sri Lanka often face serious terror charges, argue rights groups. The Sri Lankan government denies such happenings and insists that most of the asylum seekers are released immediately in a majority of the cases.

Human rights groups have been relentlessly arguing that Tamils are being persecuted under the Sinhalese-led government. The two ethnic groups were engaged in a bloody battle for more than two decades which culminated in the Sri Lankan army defeating the main group Liberation Tigers of Tamil Eelam (LTTE) in 2009.

The latest move by the Australian government also evoked a sharp response domestically.

"Australia's international obligations are reliant upon a credible processing system and we have deep concerns about how that could have been performed by video link at sea in a way which gave an individual assessment, when all the time the boat was steaming towards Sri Lanka," said the country's shadow immigration minister Richard Marles.