A prisoner who stomped on a fellow inmate's head dished out the same treatment to a cellmate while awaiting his court appearance.

Wade Dylan Junior Bartlett - who has an expletive tattooed on his forehead and a gang acronym across his cheeks and nose - admitted being behind the two violent incidents when he appeared in the Dunedin District Court yesterday.

Bartlett, 33, was supposed to appear on a charge of injuring with intent to do grievous bodily harm on Friday, but while in the cell with his two co-accused, he struck again.

Security staff at the Stuart St courthouse heard "a commotion'' coming from the cell and saw Bartlett stomping on the 21-year-old victim's head several times before they could pull him away.

The younger man, who was allegedly involved in the April prison attack with Bartlett, was taken to hospital with head injuries and discharged the same day.

When he appeared in court by audiovisual link yesterday, the left side of his face was visibly swollen and he sported two black eyes.

A Corrections spokeswoman said the appropriateness of placing multiple prisoners in holding cells at court was determined case-by-case.

"An event review is currently under way into this particular instance. While this is under way and the matter is still before the court, we can't provide any further detail,'' she said.

Bartlett was serving time at Otago Corrections Facility for offences committed in Christchurch, the court heard.

At 9.20am on April 1, he entered the exercise yard of Wing K with 13 other prisoners.

Bartlett yelled gang slogans at a building before removing his top.

The victim, Mark Quentin Waitere, 40, was isolated from others in the yard at the time and was performing leg stretches by the rear wall, the court heard.

"In an orchestrated and premeditated manner defendant Bartlett begins to punch the victim, with his right closed fist connecting with the victim's head,'' a police summary said.

The two other offenders allegedly came in and inflicted multiple blows with their fists, knees and feet.

Waitere fell to the ground where Bartlett stomped on his head multiple times.

"All defendants then parade around the exercise yard, again demonstrating what appears to be gang slogans to a prison building,'' court documents said.

"The defendants boast and applaud amongst other prisoners.''

Even the introduction of Corrections staff was not enough to put an end to the incident.

Bartlett returned to the unconscious Waitere and stomped on his head again.

The incident was captured on CCTV, police said.

The victim suffered cuts, bruises, swelling and concussion.

Some of the lacerations needed to be glued up, the court heard.

Bartlett was convicted of assault with intent to injure over the episode, was given a first-strike warning and will be sentenced in August.