Guards sprayed juvenile inmates with capsicum spray at close range during a riot in the youth justice unit of Barwon Prison that allegedly left one officer injured, the Supreme Court has heard.

CCTV footage of the Grevillea unit of the maximum security adult prison on February 13, the day of the riot, was shown to the Supreme Court on Thursday and released publicly on Friday, providing one of the first glimpses into the controversial youth justice centre.

The footage, requested by lawyers of children who argue that the unit is illegal, shows a riot starting in the communal area of the ground level.

One of the inmates is seen throwing a chair up towards a staff member as they walk downstairs towards them. As the staff member catches it, the inmate throws another chair at him, prompting a number of guards to emerge from the unit's control room.