Sources close to the legal team representing a group of ten asylum seekers on Nauru who are charged with rioting and wilful damage say their detention is incompatible with the Nauru constitution.
A hearing for the asylum seekers this week was stopped after their lawyer lodged an application in the Magistrate's Court for habeas corpus - challenging their detention at the Australian run camp on the island.
The challenge is to be heard at the island's Supreme Court on June the 7th.
Lawyer Jay Williams told the court he had been refused access to the detention camp by Australia's Department of Immigration, stopping him from interviewing his clients.
The high-powered legal team for the asylum seekers has been joined by Michael Mori, a former US military lawyer who defended Guantanamo detainee David Hicks.
He joins human rights barrister Julian Burnside QC and lawyer George Newhouse.
Australia's immigration department rejects the claims it had denied Mr Williams access to the asylum seekers, saying it had facilitated meetings on two occasions in April.
It says at no time was the lawyer prevented from meeting his clients and staff at the detention camp facilitated extensive meetings.