Detainees have been crammed into holding cells and left without enough food or water following a riot on Christmas Island, their families and lawyers say.
In the aftermath of the unrest, at least 17 detainees have been transferred off the island.
Australian Immigration Minister Peter Dutton said the riot's ringleaders were some of the country's worst criminals, and could face criminal charges.
Serco's management of the detention centre was also being investigated, he said.
The company said in a statement it had suspended three staff while it investigated a detainee's escape.
The centre was "appropriately staffed", it said.
Mr Dutton estimated the repair bill for damage at the centre at nearly $NZ11 million.
Seven detainees - five New Zealanders, a Tongan and an Afghan - suspected of involvement in the riot were yesterday flown to a maximum-security prison in Perth.
Another 10 detainees were also flown to Perth, where they arrived at the city's airport today in handcuffs and under heavy guard. One had a bandage on his face while another was limping.
Seven were expected to be transferred to the same prison as the first group. A spokesperson for Mr Dutton said two of the others required medical treatment unavailable on the island, and a third was "already scheduled to be removed from Australia voluntarily".
Tauranga barrister Craig Tuck, the lawyer for one of the five New Zealanders sent to Perth, said the Australians had refused to give him any information about his client, but he had talked to the man by phone.
The man had not yet been charged with any offences following the riot, in which buildings were torched, windows smashed and offices wrecked.
"That's indicative of how much stress people are under, being in a situation where they don't know what's going on," he said.
"They've been removed from the families, the rule of law seems to have collapsed, and now it's just a jungle mentality."
Mr Tuck dismissed the Australian government's claim that order had been restored on the Indian Ocean island.
"The situation on Christmas Island is volatile and it's not under control, and there's a lot of unhappy, concerned and scared people out there."
The mother of one New Zealand detainee still on Christmas Island said she was desperate to find out whether her son was safe.
The woman, who wanted to be known only as Kathryn, told RNZ she heard from her son Luke immediately after the riot on the island earlier this week.
He was distressed, hurt and told her he needed seven stitches.
"He told me the place was just going off, it was out of control. He said 'Mum, I don't know what to do'... I said, just crawl under a rock until it's over."
Kathryn was desperate for information about her son's whereabouts, she said.
Asylum seekers 'left in an extremely distressed situation'
Another lawyer for a detainee who was on the island until very recently said he feared the men's appeals against their visa revocations would be set back in the riot's aftermath.
He was advising his client to keep a low profile amid a groundswell of Australian public opinion against the detainees, citing a Brisbane Courier Mail article yesterday headlined 'Fast-track deportation for thug Kiwis'.
The paper said Mr Dutton was moving to "deport some Kiwis before their cases are reviewed".
Advocates, meanwhile, said asylum seekers - many from Iraq, Afghanistan and Sri Lanka - were suffering as a result of the riots.
Refugee Action Coalition spokesperson Ian Rintoul said about 20 asylum seekers were evacuated from their protected compound during the unrest, supposedly for their own protection, after fires were lit outside.
He said they told him by phone yesterday they were being held three to a cell with no mattresses in a high-security unit, before being moved to a basketball court to make room for other detainees.
They were then moved to another high-security unit, where they were strip-searched and left to their own devices, he said.
"There's already been one attempted suicide... There's no guards in [high-security unit] White 2 at all.
"They've been left in an extremely distressed situation and can't get any answers about what's going to happen to them."
Mr Rintoul said the group had been verbally abused and had been given little food or water.
The Australian Department of Immigration and Border Protection, however, said food and medical services were being provided.
No-one from Mr Dutton's office was available for interview, nor could they provide answers to written questions.
However, a spokesperson told RNZ no-one had yet been charged in relation to the riots - and that it would be a matter for the police, not immigration officials.
Breakdown of New Zealanders' convictions
The Australian government has provided New Zealand Justice Minister Amy Adams with a breakdown of offences by the 40 New Zealanders being held on Christmas Island.
They include manslaughter, armed robbery and assaulting a child or wife with a weapon. A criminal convicted of indecently treating a child is also listed. However, none are murderers or rapists.
Prime Minister John Key sparked a parliamentary walk-out on Tuesday by claiming Labour was "backing the rapists" on the island. Mr Key had repeatedly said there were rapists, child molesters and murderers there.
Ms Adams said this morning Mr Key's statements were based on previous reports provided by the Australian government.
"What we haven't known until now one or two hours is exactly what the specific make-up was on Christmas Island.
"What the Prime Minister and I have referred to, to date, has been the category of offenders we are talking about in the wider context - contains some very, very serious offenders."
Mr Key said, due to privacy reasons, an exact breakdown of the offenders' details would not be given.
- RNZ / ABC