Reports from Papua say Indonesian police have arrested four people following a meeting to mark the boat trip of Australian activists towards Papua.
The reports say 2,000 people attended the gathering at a Protestant Church in Sorong.
The Sorong meeting follows another rally in Manokwari as Papuans are awaiting the vessels.
The activists have no clearance from Indonesia to enter its waters.
Australia has said it feels it has no obligation towards the group, which could be jailed in Indonesia for five years.