Hundreds of prisoners rioted at a maximum security prison in Melbourne on Tuesday, leading to the evacuation of prison staff, media reports said.
The unrest occurred when a protest over a smoking ban at the facility spun out of control.
Television footage from the prison in Ravenhall, a suburb of Melbourne, showed prisoners with their faces covered, carrying sticks as makeshift weapons. Smoke was seen. As many as 300 inmates were involved, the Australian Broadcasting Corporation said.
"Police are currently responding to a disturbance," a police spokeswoman for Victoria state told reporters. "Staff have been evacuated as a precaution. The inmates remain contained within the grounds and a number of police units are currently on scene including the Air wing."
The smoking ban, being imposed at prisons across the state, was due to take effect at Ravenhall on Tuesday.