The disturbance followed a botched escape attempt and lasted into the next day. Prisoners took several warders hostage and fire gutted part of the prison.

At 2 a.m. on 20 July, two prisoners attempting to escape clubbed the unlucky warder who discovered them, took two hostages, and began unlocking cells. Chaos ensued as prisoners lit fires and fuelled them with oil, furniture and their own belongings. Firefighters had to retreat under a barrage of bricks and other missiles.

Armed police, warders and troops stood guard around the prison, discouraging any attempts to break out with warning shots and high-powered hoses. Eventually the lack of food, fuel and shelter took its toll, and the prisoners surrendered 33 hours after the riot began.

The damage at Mt Eden was extensive. Inmates destroyed basements, storerooms, the kitchen, chapel, watch house and 61 cells, and there was extensive damage to the roof. Following the riot there were calls for the aging prison, built in 1917, to be demolished. Instead, prisoners were relocated while the gutted shell was rebuilt.