Detainees at Christmas Island's immigration detention centre have been injured in a clash with police who seized back control after a riot sparked by the death of an escaped refugee.
Immigration Minister Peter Dutton said five detainees sustained minor lacerations and injuries "as a result of their interaction with the police and their refusal to comply with directions".
Mr Dutton said police had used reasonable force against the detainees, the vast majority of whom were serious criminals including rapists and murderers, adding that a significant number of them were from New Zealand.
"The population has hardened within the Christmas Island immigration detention centre," he said.
"While the number of boat people drops in detention, the number of people in detention who have been involved in serious criminal activity or had their visas cancelled through a failure of the character test - those numbers increase."
Tear gas was used but he did not know if rubber bullets were fired, which a detainee reported to ABC radio.
Another detainee told the broadcaster some rioters had been armed with chainsaws and firebombs.
The riot was sparked after a small group of Iranian detainees staged a protest over the death of escapee Fazel Chegeni Najad, an Iranian Kurdish man, on Sunday.
The Department of Immigration and Border Protection said a core group of detainees had built barricades and threatened to use weapons.
Mr Dutton said a sixth detainee had been evacuated for "minor injuries and a medical condition unrelated to incident", although a Greens source told reporters the man had been evacuated after trying to overdose, having helped himself to drugs from the medical centre.
Mr Dutton said the detainees had caused more than $1 million in damage and would be prosecuted.
"People who think they can operate outside of the law have another thing coming," he said.
While the perimeter fence was not breached, security needed to be reviewed, Mr Dutton said.
"At no stage was there any threat to anybody in the Christmas Island community. There are lessons to be learnt though.
"The fact that this incident started in the first place, we need to examine the response initially by the officers - all of that will be examined in due course and if we need to provide additional security, that's what we'll do."
Christmas Island Shire president Gordon Thomson said Mr Chegeni Najad died from injuries sustained when he fell into a pit as he ran through the dark after jumping the centre fence.
Mr Chegeni Najad was granted refugee status in Australia after fleeing persecution in Afghanistan, but was convicted of assaulting a fellow detainee at the Curtin immigration detention centre in WA in 2011.
His sentence was overturned on appeal, but the conviction stood.
