Papua New Guinea authorities have stopped two refugees from Australia's offshore detention centre on Manus Island from travelling to Port Moresby to give evidence in the Supreme Court.
Behrouz Boochani and Aziz Adam were summonsed to appear in a compensation case against the PNG Government, which was found to have illegally detained the men on Manus Island between 2013 and 2016.
But security staff at the island's airport said the men did not have permission from PNG Immigration authorities to board the plane.
Mr Boochani said it was clear the PNG Government did not want them to give evidence.
"Obviously they did not want that we go to court as a witness and tell our stories there and tell about the situation in Manus," he said.
Lawyers for the PNG Government had asked to cross-examine the men about the change in arrangements on Manus Island after the Supreme Court found the detention of asylum seekers there breached PNG's constitution.
The Government has given evidence saying it ceased detaining the men on April 27, 2016, the day after the Supreme Court handed down its ruling.
Lawyers for more than 700 asylum seekers on the island say the detention continued for at least two weeks after the judgment was handed down.
The date detention ceased is a critical factor in whether the men's compensation claim — which mirrors a successful claim in the Victorian Supreme Court — can proceed.
But Mr Boochani said the decision to block him and Mr Adam from travelling to Port Moresby showed the refugees were still effectively in detention.
"Still we don't know our rights in this country," Mr Boochani said.
"The Government lawyer told the court that these guys are allowed to go everywhere in PNG, but today this proved that we are not allowed to leave this island and we are hostage by the Government."
Many men on Manus who have refugee status have previously been allowed to travel around Papua New Guinea, without seeking permission from PNG's Immigration and Citizenship Advisory Service ICSA.
PNG's chief migration officer, Solomon Kantha, said the Immigration and Citizenship Service Authority (ICSA) denied stopping the men from boarding the plane at Momote Airport.
"No ICSA officers [were] at the airport and no-one had any knowledge of their travel to Port Moresby," Mr Kantha said in a statement.
"These allegations are not true."
"The Air Niugini ticketing officer advised that the two gentlemen bought their tickets to Port Moresby online.
"They presented themselves to the ticketing counter yesterday morning and were requested by the Air Niugini staff to bring in an immigration officer to identify them before boarding passes could be issued.
"They went out of the terminal and never returned. No-one called ICSA to identify them.
"Air Niugini on Manus had tightened their screening process to ensure the RPC [regional processing centre] residents travelling out on their own accord provide the necessary details of their identity before they board the plane out of Momote Airport.
"The security/identity check is a normal process put in place at the request of ICSA to ensure residents from the RPC have the necessary approval and also ensure the duty of care to residents is accorded."