A group of 157 Sri Lankan Tamil asylum seekers at the centre of a High Court battle were almost sent back to India on orange lifeboats they were taught how to operate, refugee advocates and lawyers say.

The Tamil Refugee Council says some of the Tamil asylum seekers who were sent to Nauru last Friday night have given a harrowing account of their time on board an Australian Customs ship.

The council's convenor Trevor Grant says he was told nine men were taught to drive the boats and told they would be dropped off hours from the Indian coast.

"This was about halfway through the trip," he told ABC News24.

"They were split off into threes and in each boat three men were given instructions on how to drive them.

"One of the great problems, of course, is the instructions were given in English and these men have a very limited grasp of English."

Lawyers for the Tamils, who left the Indian state of Pondicherry in mid-June, say the move happened on July 14, while they were challenging the group's detention on the high seas in the High Court.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 3 minutes 20 seconds 3 m 20 s Sri Lankan asylum seekers 'trained to drive orange lifeboats' ( James Glenday ) Download 6.1 MB

Hugh de Kretser, executive director of the Human Rights Law Centre, says his clients were "terrified at the prospect of being dumped in the ocean on lifeboats without experience in navigating or operating a boat, and having to take the responsibility for the families on those boats".

Officials told the asylum seekers the move to put them on the lifeboats was an Australian Government decision, and they had to obey.

"The people, or the men were told to prepare at any time for the boats to be dropped into the ocean," Mr Grant said.

"They were shown a map of Sri Lanka and India, and they pointed to a southern Indian coastal city, and they were told that, 'you may reach that coast within five hours'".

Mr Grant said he had been given of details of what happened on board the Customs ship by a 34-year-old man who is now on Nauru.

He did not want the man's name released publicly, but says he regards him as a credible witness.

"He said they were told by Customs officers to be prepared [for all] 157 to be put on the boats at any time," he said.

"He said they were shown a map, and on the map was pointed out a city on the south coast of India called Kanyakumari, and he said: 'They told us in five hours, you'll see the shore'.

"He indicated to us the instruction was fairly minimal and the idea of them being in charge of these boats for five hours on the Indian Ocean was a very scary prospect."

Fathers separated from children on Customs ship, asylum seeker says

Mr Grant said the man claimed fathers were only allowed to see their children every three or four days while the group was being held on the Customs ship.

He said the asylum seekers were not given enough food, clothing or sanitary pads.

"His words to me were, 'We were treated like animals'," he said.

"He said he never believed that asylum seekers would be treated in Australia or by Australian officials in such a manner."

The asylum seeker confirmed details about the high seas detention given to the High Court by Government lawyers last month that the Tamils were kept in the hull of the Customs ship.

Mr Grant said the man claimed fathers were only allowed to see their children every three or four days while the group was being held on the Customs ship.

"He said that they were kept for all but three hours a day in the hull of the boat, there were no windows, there were 78 men kept in one room and the women and children were separated into two other rooms.

"He said that they were hungry, he said that the children were crying out regularly for milk, he said the way the Customs officials dealt with that was to shut the door and walk away."

Lawyers are challenging the Commonwealth in the High Court over the way the Sri Lankans were first intercepted and then treated.

Mr de Kretser, who says he has only been able to speak to 15 of the 107 adult asylum seekers who were on the ship and are now being held on Nauru, has accused the Australian Government of not respecting the rule of law, transparency, or basic human rights.

"I am deeply concerned about how our clients have been treated and I am deeply concerned for their wellbeing in detention on Nauru," he said.

"They were denied basic legal rights (in India), including being unable to lawfully work, send their children to school, or have freedom of movement."

He says he has only had limited access to his clients.

"Some revealed safety fears in India also, and again, we have not been able to properly explore these issues."

Scott Morrison disappointed asylum seekers did not take up Government's 'humanitarian plan'

Indian consular officials were to have helped determine the asylum seekers' identity and residency while they were being held at the remote Curtin detention centre in Western Australia, but the Tamils refused to talk to them.

Mr Morrison has rejected allegations the Tamils were denied access to lawyers before being sent to Nauru, saying they had been allowed to speak to lawyers before opting not to speak to the Indian officials.

"Then 157 people coincidentally decided not to take up the offer of talking to Indian consular officials," he told Macquarie Radio.

"We don't know what they said, and they [the lawyers] say that they did not give that advice. If they wanted to talk to Indian consular officials then, well, clearly, they weren't very persuasive."

The lawyers have rejected any assertion they advised their clients not to speak to Indian officials.

Mr Morrison said he was disappointed the Tamils did not take up the Government's "humanitarian plan" of going back to India.

"We had teenagers on that ship who were born in India for goodness sake. They spent all their lives there."

People smugglers using Refugee Convention as 'death voyage' tool, says Morrison

Mr Morrison has repeatedly refused to confirm whether attempts had been made to return the latest batch of Tamil asylum seekers to India using Australian orange lifeboats, citing "operational matters".

Orange lifeboats are a key part of the Government's plan for turning back asylum seekers, though their use is always shrouded in secrecy.

The lifeboats have been used on several occasions to return asylum seekers to Indonesia.

The Immigration Minister is seeking to reshape Australia's interpretation of the 1951 UN Refugee Convention to make it easier to send people back to home countries.

Mr Morrison has confirmed he is seeking a High Court ruling that could see asylum seekers told to change jobs to avoid persecution.

"If someone were to say, 'I can't go back there, because I will do this sort of job and do that sort of job [that] will put me in a position of exposure,' well, there are things that are in a person's control," he said.

He says the Abbott Government is committed to the UN Refugee Convention, but has a problem with how it has been interpreted by lawyers and others.

"Our courts draw on all of their interpretations and what started out being a pretty sensible document over time has had layer upon layer upon layer and it is now being used as a tool by people smugglers to basically run death voyages," he said.

Mr de Kretser says the asylum seekers still have a case against the Commonwealth, even though they have now been taken to Nauru to have their claims processed.

The 157 passengers are the first to be transferred to immigration authorities in nearly seven months. In comparison, more than 4,000 asylum seekers arrived by boat in July last year.