A man who has identified himself as a relative of some on board the boat carrying 153 asylum seekers told an interpreter at least 11 had been previously jailed and tortured in Sri Lanka.

He described gruesome details of torture he had personally endured under the Sri Lankan regime including being bashed with a plastic pipe filled with sand and having rope tied to his thumbs and hung from the ceiling.

''One of [the asylum seekers], a man in his thirties, was arrested in the final days of the war in 2009 and jailed in Colombo, where he was tortured. His relatives had to pay several thousand dollars to get him out of jail,'' the man told an interpreter from the Tamil Refugee Council.

''He then fled to India. Like many others, he lived there in a refugee camp under threats of intimidation from Indian authorities, who have connections with the Sri Lankan government. It's why he, along with the others, took this boat to Australia.''

The man has not heard from his relatives since last Thursday.

The federal government has maintained its silence on the whereabouts of the boats.

Greens Senator Sarah Hanson Young said she would call on the newly appointed Senate to vote to condemn the government's actions on the high sea.