The Asian Human Rights Commission says there must be an investigation into last month's killing of a Papuan man by five soldiers.
The Commission says Derek Adii was stabbed to death after complaining at the way the soldiers were treating women and children passengers on a vessel at Samabusa Nabire Port in West Papua.
After the stabbing, Mr Adii's body was thrown into the sea.
Authorities in Nabire concluded the soldiers were defending themselves and claimed the victim fell into the sea because he was drunk.
They maintained this view despite numerous passengers giving eye-witness accounts of the incident.
The Commission says it wants an immediate and impartial investigation into the killing and for the prosecution of the perpetrators.
It says accountability mechanisms have to be made effective in West Papua to avoid a further deterioration of the security situation.
The Commission is also writing to the UN Special Rapporteur on extrajudicial, summary or arbitrary executions and the Special Rapporteur on the rights of indigenous peoples.