Asylum seekers who were forcibly returned to Indonesia by lifeboat have given the first detailed account of their ordeal, and a unique insight into the Federal Government's Operation Sovereign Borders.

New video footage of their journey has also emerged, despite Australian Government attempts to keep the turn-back operations secret.

The passengers who are now in detention in Indonesia have given the ABC's 7.30 program their accounts of being forced onto an orange lifeboat after being held on the Australian Customs ship Triton off Christmas Island for up to a week.

Iranian asylum seeker Arash Sedigh, 35, said it was the second time he had tried and failed to reach Australia and been put on one of the orange boats, bought specially for the purpose by the Australian Government.

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Mr Sedigh said that during their detention on board the Triton he was separated from the other passengers so he could not warn them about their imminent return.

He claims officers "punched" him before putting him onto the lifeboat.

"I asked [sic] them, 'We will die in this orange boat, it's not suitable for passing the ocean'," Mr Sedigh said.

"They told me, 'That's not our problem, that's yours. If you die in the Indonesian water, [it] makes Indonesian government in trouble and responsible. That's not our problem'."

Mr Sedigh's wife, Azi, has told 7.30: "I was just screaming, I kept saying, 'This boat of yours is not suitable for me to board it'."

"I was holding to the sides of the boat that they took us to ... I was just screaming. But the only thing they did was to pull me forcefully towards that boat," she said.

Mr Sedigh said he had threatened to kill Customs officers after he had earlier requested medical attention for a pregnant woman and other sick passengers, a request he alleged was refused.

He also claimed that after demanding to know what was going to happen to him and his fellow passengers, officers said: "We don't know, you have no rights, you have no rights."

He said that at one point they heard they were to be transferred to Christmas Island "very soon".

Instead, the asylum seekers were placed onboard the lifeboat and towed to within a few hours' sailing time of the Indonesian coast.

Asylum seeker says passengers treated 'like prisoners of war'

A Pakistani asylum seeker, who wanted to be known only as "Mr Dar" because he had been targeted by Islamic militants in Pakistan and feared for his family, said he and fellow passengers had been treated "like war prisoners".

"But all people were innocents, small babies, ladies, pregnant ladies and everybody was disturbed and in difficulty. Otherwise, why [would] we go there?" he said.

Mr Dar said the lifeboat was "very small and very smelly".

"This boat is like a grave," he said.

"The people [were] neck to neck and knee to knee ... somebody vomiting, the bad smell of the vomiting, other people start smoking, vomiting. All the people, one by one, vomiting."

The ABC spoke to a dozen passengers who left Indonesia on a wooden fishing boat on December 27 and washed up in the lifeboat at Pangandaran on the south coast of West Java on February 5.

Some agreed to give in-depth interviews but many appointed Mr Sedigh as their spokesman and said they agreed with his version of events.

Questions put to border protection officials

The ABC has put detailed questions on the turn-back operation to the Australian Customs and Border Protection Service, including allegations of mistreatment made by the asylum seekers.

A spokesman for Immigration Minister Scott Morrison did not answer specific questions.

He said Navy and Customs and Border Protection officers working under Border Protection Command were "well trained and act in accordance with that training and the guidelines and protocols established for these operations".

"The Government rejects unsubstantiated allegations of inappropriate conduct made against our Navy and Customs and Border Protection personnel," the spokesman said.

The new interviews and exclusive footage of the asylum seekers' journey is the first instalment of a two-part special investigation into Operation Sovereign Borders.

The United Nations High Commissioner for Refugees (UNHCR) told the ABC it had concerns about turn-back operations, and requested details from Australia in February.

After not receiving a formal response, the UNHCR has been interviewing asylum seekers about their experiences during the turn-backs. UN officials are collating the responses.

Know more? Email: investigations@abc.net.au.