The Christmas Island riot was inevitable given the influx of criminals joining the general asylum seeker population at the detention centre, says a former Australian immigration insider.
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 at the hands of the rioters.
The Australian government said it took tear-gas and some use of force to quell unrest and regain control of the detention centre yesterday. Australian Immigration Minister Peter Dutton said claims that some of those involved in the disturbances were armed with gardening equipment will be thoroughly investigated.
Steve Brooker was a mental health manager for International Health and Medical Services with responsibility for services on Christmas Island, Nauru and Manus Island. He resigned in May in protest at staff cuts.
He said conditions in the centre created tensions for detainees and staff.
"Sometimes there is just a match that is thrown onto a tinder box as has happened this week and things just flare up unexpectedly, but also expectedly because you can generally see that some of these things could have been predicted."
Mr Dutton has also rejected a claim by the Maori Party that some people detained on Christmas Island were convicted of minor crimes such as shoplifting and traffic offences.
He has stressed that many of those held at the detention centre on the island had their visas revoked after serving jail terms of more than a year for serious offences, including rape and assault.
He said no one was jailed for 12 months for shoplifting and it defied common sense to say so.
Meanwhile, a lawyer representing a New Zealand detainee on Christmas Island said she feared for his safety.
The lawyer, who wanted to be known only as Susan, told Morning Report she had not spoken with her client since the disturbances began.
She said the Australian immigration department needed to do more to protect detainees.
"The department is not looking after their welfare. I have a real fear that my client's safety is compromised."