A number of inmates and officers are being treated for injuries including dog bites after a large riot at Melbourne's Metropolitan Remand Centre was quelled.
The riot ended just before 3am today, after a hold-out group of 50 prisoners was brought under control.
One police officer needed treatment for exposure to pepper spray and three prison staff also received minor injuries.
Four prisoners have been taken to hospital at Port Philip Prison with injuries, including two with dog bites.
A fifth prisoner needs hospital treatment for a suspected broken jaw.
"I am deeply relieved that no-one was seriously injured," Victoria's police minister Wade Noonan told reporters in Melbourne.
"But I would like to make it absolutely clear the events of yesterday were unacceptable to the government and unacceptable to the Victorian people.
"This criminal behaviour will not be tolerated."
He said there would be a full investigation into the riot and its triggers, which likely included the introduction of a statewide jail smoking ban.
All of Victoria's prisons remain in indefinite lock-down to prevent any further flare-ups.
Corrections Commissioner Jan Shuard says there will be no backdown on the ban on smoking in Victorian jails, which has now taken effect.
"It is likely at the heart of what happened yesterday," Ms Shuard said.
"Smoking is unlawful in Victoria's prisons as of today so that (ban) will continue."
She said the riot may have occurred at the remand centre because it holds shorter-term inmates who had less time to adjust to the ban.
Victoria's prison system has been preparing for the transition to smoke-free for months, she said, and all inmates had access to quit medications.
The riot started about midday on Tuesday with up to 300 inmates smashing doors and setting fires.
Heavily-armed police entered the prison just before midnight to take on a group who defied orders, given over a loud speaker, to return to their cells.
At no time did inmates attempt to breach the outer wall of the prison.
With just six weeks until smoking bans are introduced at NSW prisons, Corrective Services NSW Commissioner Peter Severin says he'll be seeking a briefing from his Victorian counterparts to make sure similar scenes don't occur in NSW.
"I want to ask what were the issues that caused it to be so extensive as it seems to have been," he told ABC.
