The Australian Immigration Department says three asylum seekers were stopped from escaping from the asylum detention centre run by Canberra on the Papua New Guinea island of Manus.
The Department's Communications Manager, Sandy Logan, says three men climbed the fence of the centre over the weekend, and ended up in the water.
PacNews reports they were rescued and one was treated at the health clinic.
They were among 40 men from Iran, Iraq and Afghanistan who were moved from Australia to the detention centre on Saturday.
Their arrival was in exchange of 30 other men who were moved from Manus to Nauru on Saturday.
Australia has been criticised by international organisations, such as the UNHCR, for the way it runs its detention centres abroad.