Amnesty International says a new charge laid against the Manus Island asylum seeker who escaped to Fiji could violate Papua New Guinea's law of double jeopardy.
Loghman Sawari was arrested after a court hearing in Port Moresby on Tuesday, where he was on trial for using false information to obtain a passport.
That charge was made under the Passport Act and Amnesty said the new charge was virtually identical but had been laid under the Migration Act.
Amnesty's Kate Schuetze said the new charge could indicate the prosecution was in danger of losing the current trial.
"They are by and large the same charges. This is violating his right to a fair trial and in breach of the double jeopardy law," said Ms Schuetze.
"It seems like they have laid these charges just at the time when the court is considering an application to dismiss the previous charges because of lack of evidence."
Ms Schuetze said Loghman Sawari was still in police custody.
