The leader of the Greens party in Australia, Bob Brown has called on the Minister for Foreign Affairs to get Indonesia's assurance over the safety of a Papuan human rights worker.
Jonah Wenda was arrested on Thursday.
He made a mobile phone plea to alert friends but his phone has now gone quiet.
It is thought that he was arrested by Indonesian police near the Papua New Guinea border and taken to West Papuan capital, Jayapura.
Friends say he 'is sick and needs urgent medical attention'.
Senator Brown says the Mr Wenda is in real danger, in view of the record of death and torture of West Papuan activists previously taken into custody.