A constitutional challenge to Australia's tough border protection policy will be taken up in Papua New Guinea's Supreme Court on Tuesday, with lawyers expected to push for access to detainees housed on Manus Island.
Loani Henao, who brought the challenge on behalf of opposition leader Belden Namah, also says he has communicated with an asylum seeker housed on Manus Island.
"What we're trying to do is get orders from the court to get to Manus," Mr Henao told AAP.
He said a lone asylum seeker on Manus responded to a newspaper advertisement inviting interested parties to join the challenge.
"He's an Afghan. His wife and five sons were killed," Mr Henao said.
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"He says they were handcuffed when they went to Christmas Island."
Lawyers seeking to talk to asylum seekers were earlier this year prevented from doing so, despite having the backing of a court order.
Mr Henao's comments come as PNG gears up for a second round of hearings into the asylum-seeker detention centre.
An earlier challenge to the centre on Manus Island was dismissed by the courts on procedural grounds, a move welcomed by Mr Henao at the time.
The challenge is expected to be under way when the government of Peter O'Neill introduces laws in September to block further challenges to the centre.
The laws will also create a new visa class for asylum seekers resettled in PNG, and may also consider options for allowing resettled asylum seekers to work in the private and public sectors.
Australian Prime Minister Kevin Rudd last month announced all asylum seekers who arrive by boat will be sent to PNG.
Mr O'Neill was recently quoted in Fairfax newspapers as saying some asylum seekers processed in PNG will have to be resettled in Australia.
There are currently 223 asylum seekers housed on Manus island, a PNG province located just two degrees from the Equator.
