Police have detained 41 people in the town of Fakfak in the Indonesian province of Papua, for allegedly hoisting the banned Morning Star flag at the weekend.
Papua Police spokesman Senior Commander Agus Rianto said three of the detainees hoisted the flag in front of the former people's self-determination vote office.
The Jakarta Post says all 41 are former political prisoners.
Under the Criminal Code, the detainees can be charged with plotting a coup.
The flag has long been a symbol of the region's separatist rebellion, with the Papuan Tribal Council urging the government to recognize the flag as a cultural symbol for Papuans.