Rampaging asylum seekers have left a $60 million damage bill to the Nauru detention centre, with dozens arrested over the riot.
They torched newly constructed accommodation blocks, the health centre, offices, the dining room and vehicles.
Only the kitchen and recreation facility remain standing and usable.
"It is quite extensive damage," a spokeswoman for the Immigration Department told AAP.
No staff were injured in the unrest on Friday but a number of residents were treated in hospital for minor injuries and some for pre-existing conditions.
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The spokeswoman said the damage bill was estimated at $60 million.
She said their latest information was that 125 of those allegedly involved in this destruction were now in jail, with some 58 charged by Nauru police.
With accommodation for more than 600 trashed, residents will be housed in tents erected on the site planned for a new detention facility.
"We will have temporary ablution blocks installed and temporary water supplies put in place and meals will be prepared at the original kitchen," she said.
Unrest at the Nauru detention facility started earlier last week with peaceful protests at the delay in processing of asylum claims.
The situation escalated on Friday afternoon with some 150 of the 545 male detainees setting fire to buildings.
Immigration Minister Tony Burke said he was waiting for reports on the full extent of damage.
He warned those involved that he had extensive powers to refuse or cancel visas on character grounds.
Foreign Minister Bob Carr said advice to him indicated the rioting was unrelated to Prime Minister Kevin Rudd's announcement of the new PNG solution on Friday afternoon.
He said those detained by Nauru police should understand that they hadn't impressed anyone in Australia.
Senator Carr admitted Australia would have no choice but to rebuild.
"As a destination country we have got to stump up the money for the accommodation and processing of people who arrive without visas," he told Sky News.
The opposition blamed Labor.
Opposition leader Tony Abbott said riots were a problem when you couldn't stop the boats.
"As long as you have got illegal arrivals by boat, as long as you have got people in immigration detention, you are at risk of riots," he told reporters in Melbourne.
Immigration spokesman Scott Morrison said this wasn't the first detention centre to burn down under Labor.
"If you need any demonstration of Labor's ability to implement offshore processing ... then look at the fires on Nauru," he told reporters in Melbourne.
