Three asylum seekers held on Manus Island broke out of detention at the weekend, scaling a fence and wading into the ocean.
Another asylum seeker was treated at a medical centre after he allegedly smashed his head repeatedly against a wall.
The incidents come amid reports of a protest by asylum seekers on the island, with claims some Iranian and Iraqi men are holding a sit-in at the camp's reception centre and are refusing to eat.
An Immigration Department spokesman said the escapees were caught and returned to the centre.
Refugee advocates claimed the men, who escaped on Saturday night, had been trying to take their own lives by drowning in the sea.
The centre, built on a remote island in Papua New Guinea, is just a few metres from the beach. The island has 221 asylum seekers.