Three of the 151 asylum seekers that were transferred to Nauru for processing have since opted to return to their homeland, bringing the total number on the island to 148.
Nauru is hosting the detention camp, at the request of Canberra, for people seeking refugee status in Australia.
A similar camp on Manus Island, off Papua New Guinea's north coast, is not expected to open for at least a month.
On Friday, the fifth group of asylum seekers arrived on the island with 31 Sri Lankans.
Over the past two weeks, five groups of asylum seekers have been flown in to Nauru aboard a chartered Airbus A319. There are 128 Sri Lankans and 20 Iranians - all are men.
The Nauru government's Bulletin edition says it's anticipated that more arrivals will take place over coming weeks.