A total of 46 people were arrested on Thursday in Jayapura in Indonesia's Papua region during rallies in support of Papuan membership of the Melanesian Spearhead Group.
Victor Yeimo of the United Liberation Movement for West Papua, or KNPB, says five of them suffered serious injuries after being hit by police when they were giving speeches outside the University of Cendrawasih.
He told the Catholic news service, ucanews.com, that one of them was hit in the head with a rubber bullet.
Mr Yeimo says another 25 people were arrested in Wamena.
They were showing their support for the application by the United Liberation Movement for West Papua to join the sub-regional political body, the MSG, which is made up of the five independent Melanesian countries and the Kanaks of New Caledonia.