Staff are back in full control of the Christmas Island Detention Centre, the Australian Department of Immigration says.
Trouble broke out at the centre, which is operated by Serco, early on Monday (NZT) after the death of an asylum seeker who had escaped.
The facility houses both asylum seekers and New Zealanders with criminal records awaiting deportation.
Detainees on the island described fires and damage to facilities, with some saying they feared for their safety from those who had been rioting. Others said they felt unsafe as armed guards and police prepared to enter the facility.
More on the reaction to the unrest in New Zealand
Australian Immigration Minister Peter Dutton said five detainees were injured during the operation to regain control of the detention centre.
Mr Dutton said tear gas was used by authorities to bring the unrest under control but did not confirm the use of rubber bullets.
No police officers were injured, he said.
"I understand there have been five detainees who have received minor lacerations and injuries otherwise as a result of their interaction with the police and their refusal to comply with the directions provided by the Australian Federal Police."
He said security arrangements at the centre would be reviewed, with additional funding provided to boost security.
'Core group of criminals'
The Australian Department of Immigration earlier issued a statement to declare the facility was under control, after Mr Dutton had blamed a "core group of criminals" for the riot.
He warned those who had damaged property would face the full force of the law.
The department's statement said the majority of detainees cooperated with service providers in restoring control.
"This morning's operation to regain control of the centre, and ensure the welfare of those not participating in criminal damage activities, was achieved largely through negotiation and cooperation with detainees," it said.
"The centre remains calm, with detainees secured in undamaged areas of the centre.
"Food, fluid and medical support continues to be provided."
The statement said some force was used on a core group of detainees who had built barricades and threatened to use improvised weapons.
Service provider staff would conduct a sweep of all compounds to search for contraband, including weapons, before detainees were moved back into normal accommodation areas.
"A full survey of damage to the centre is yet to be completed, but some common areas appear to be severely damaged," the statement said.
"Work to repair the centre will be undertaken as a priority."
Back-up staff were flown to the island this morning to relieve workers who had been under pressure since chaos took hold, with federal police reinforcements also sent.
The events were prompted by the death of Iranian Kurdish man Fazal Chegeni, who was found dead on Sunday after escaping from the detention centre.
Mr Dutton said a coronial inquiry into the circumstances surrounding the death of Mr Chegeni would be conducted.
"As I'm advised there are no suspicious circumstances in relation to the death," he said yesterday.
Barricaded detainees 'armed with petrol bombs, chainsaws'
This morning, New Zealand Labour corrections spokesperson Kelvin Davis said he had spoken to some detainees by telephone as armed guards prepared to enter the centre.
"Things have really kicked off, the riot squad has moved in waving their batons, apparently gas canisters have been fired," he said.
"There's reports of people being hit with rubber pellets, people are barricading themselves in their rooms, just trying to keep themselves safe."
One detainee, Tuk Whakatutu, told Morning Report the situation was tense.
"The riot squad's all geared up ready to come in. Everything's barricaded up, all the young fellas are all tooled up... They've got petrol bombs, they've got machetes, they've got chainsaws, metal bars; all sorts."
The rioters had the run of the compound and had broken into garden sheds to look for weapons, he said.
"It's just going crazy. I want nothing to do with it, but all the young fellas are gee'd up, they want to go to war with them."
He said the group that was armed was made up of mainly New Zealanders and Pacific islanders.
Another detainee, Ricardo Young, said sirens and water sprinklers were going off and surveillance drones were in the air. Fires were everywhere, he said.
But Christmas Island government administrator Barry Haase this afternoon played down the level of violence at the centre. The situation had been well handled by the police and Serco, he said.
"There is a lot less upheaval than perhaps has been generally reported."
- RNZ / ABC