More than 150 Tamil asylum seekers on board an Australian border protection vessel are being detained in windowless locked rooms with men kept apart from their families against their will, newly released high court documents have revealed.

A statement of claim document submitted to the court by lawyers acting for 86 of the 153 asylum seekers also reveals that they have had no opportunity to deliver their protection claims – despite all claiming to be refugees – and had no access to a qualified translator despite almost all being unable to speak English.

The document shows that lawyers will challenge the legality of the detentions on the vessel, which Guardian Australia understands to be the customs ship Ocean Protector.

Lawyers will also argue that any decision to move the asylum seekers straight to offshore detention would be unlawful.

The Australian immigration minister Scott Morrison has refused to offer any public comment on the fate of the 153, who were intercepted by Australian border officials in late June after departing by boat from southern India on 11 June – meaning they have been at sea for over a month.

The high court hearing has been the only public mechanism to obtain information about what is happening to the 153.

The statement of claim, written after lawyers had the opportunity to speak to their clients on board the vessel, states the immigration department have only requested basic information from the asylum seekers such as names, dates of birth and addresses. They have not been asked to discuss their reasons for leaving India or been told where the Australian government is planning to take them.

At a high court hearing last week, counsel for Morrison argued that because the 153 were intercepted outside Australia’s territorial waters, they had no rights under the Australian Migration Act.

The court document show that lawyers plan to challenge the legality of the asylum seekers' detention under executive powers and the Maritime Powers Act.

Last Thursday the human rights barrister Julian Burnside said the detention of the 153 was tantamount to piracy.

The UNHCR has voiced “profound concern” at the treatment of those on board and those on a separate boat carrying 41 asylum seekers from Sri Lanka who were subsequently handed over the Sri Lankan navy in an unprecedented on-sea transfer.

At a hearing last week, the government gave the high court an undertaking not to hand the 153 asylum seekers to the Sri Lankan navy without 72 hours written notice.

Morrison has been contacted for comment.

It is expected that the case will be heard at the end of the month after its preliminary hearing on Friday.

