A Tamil man living in Australia has detailed shocking claims of rape and torture at the hands of Sri Lankan army intelligence.

Last year almost half of the asylum seekers who arrived in Australia were from Sri Lanka, which recently emerged from 30 years of brutal civil war.

The Government has been sending Sri Lankans home, claiming the threat of war and persecution is over.

But one Sri Lankan Tamil living in Australia has told the ABC's 7.30 a very different and disturbing story.

Kumar, as 7.30 chose to call him, says just three weeks ago he was abducted, raped and tortured by Sri Lankan army officers.

"I was naked and no place to sleep, except the floor like a dog. I felt like dying but I thought of my kids and family back here," he said.

Kumar arrived in Australia in 2008. He fled Sri Lanka after being interrogated and accused of links to the Tamil Tigers.

He says he was working as a school bus driver when he was coerced by the Tigers to deliver parcels for them.

"I got afraid and I thought it's not safe to live in Sri Lanka any more," he said.

Kumar's family joined him in Australia last year. In March, he needed to return home as his uncle fell ill.

Less than a week after he arrived home to manage his uncle's restaurant, Kumar says he and his brothers were abducted at gunpoint by two men in a white van.

He was blindfolded and taken to a dark room with "dried blood" on the walls.

He says the men claimed to be army intelligence officers and grilled him about links to the Tamil Tigers, which he denied.

"They came back and again started hitting me with a log at my back and now I've got a spine problem as well," Kumar said.

"The two guys were drunk and they came to me and they just put their hand on my body and they just rubbed me and I had some sexual torture as well."

On the fourth and final day of his ordeal, Kumar's captors branded his back with hot irons.

"I thought that's the end of my life and I just fainted," Kumar said.

"When they see my back they will know what has happened to me recently, because a lot of stories [do not] come out from Sri Lanka.

"I can't forget. No-one wants to get these kinds of things in their life.

"I pray to God. No-one must get this kind of punishment."

'Believable'

Kumar says he only made it home because his uncle paid a $20,000 bribe to his captors.

Soon after he returned Kumar went to see his local doctor, a fellow Sri Lankan Tamil who issued a referral for Kumar to get urgent psychiatric treatment for his trauma.

The doctor was so horrified by Kumar's injuries that he also sought help from the Tamil Refugee Council.

The council consulted Louise Newman, an expert adviser on the mental health of asylum seekers.

Ms Newman says Kumar's is a "credible story".

"He provides detail and is very preoccupied with some of the minute details of the actual atrocities that were performed on him which is very typical... of the accounts we get from people who have been through these sorts of experiences," she said.

Gordon Weiss, who was the United Nations spokesman in Sri Lanka during the civil war, agrees Kumar's story is believable.

"There have been a series of reports in just the last few months from the US state department, from Human Rights Watch, from the UN high commissioner for human rights, detailing this kind of treatment," he said.

"One has to remember that the people in charge of Sri Lanka at the moment have got a long history stretching back to the 1980s of using torture and abduction in order to suppress segments of the population."

Transparent

But Sri Lanka's High Commissioner to Australia, Admiral Thisara Samarasinghe, says the allegations are false.

"If he has been treated in the manner that he has just explained by you, he is welcome to come and present it to me or present it to any government authority with his name and identity," he said.

"Sri Lanka is transparent. Our system of judiciary and investigation is transparent."

The Australian Government has just returned 38 of the Sri Lankan asylum seekers who arrived by boat at Geraldton in Western Australia earlier this month.

Foreign Minister Bob Carr says there is no evidence their asylum claims are valid.

"Since 2010 there has been no evidence of returnees being discriminated against or arrested, let alone tortured," he said.

"I think it's wrong to say Tamils live in fear and are fleeing their country."

Kumar's injuries mean he cannot work and is now in danger of losing his visa.

If that happens he faces deportation within a month, so his next step would be to apply for asylum.