Two Corrections officers have been stood down on full-pay after a punch-up in front of inmates over the distribution of milk at Rolleston Prison.
The prison's medium security Kowhai Unit was locked down and a female staff member had to flee after the fight erupted in the control room about 2.30pm on Friday.
A source has told The Press the fight began after a junior officer gave inmates milk, and was allegedly punched in the face by one of his superiors.
During the fight, blood splattered against windows and furniture was broken, the source said.
The junior officer was later seen with a bandage on his head, but it is understood he had only minor cuts and bruises.
Rolleston Prison manager Mike Howson confirmed two Corrections officers had been stood down pending an investigation into the incident.
There was no risk to public safety at any time, Howson said.
"Corrections demands the highest standards from its staff as they manage some of the most challenging people in the country and all staff must adhere to the department's code of conduct.
"Any breach of this code is treated seriously."
Howson declined to comment further until the investigation determined what had happened.
Corrections Association president Bevan Hanlon said he was unaware of the fight but it sounded "very unusual" and "not a good look" for Corrections.
"[Corrections staff] are supposed to be pro-social role models, teaching prisoners to use options other than violence."
He knew of only two or three similar incidents in the last decade. "[Prison] is the sort of environment where [staff] have got to look after each other - that's why it's unusual."
Officers were trained not to give prisoners anything, he said.
"I know it's only milk but there's no difference between that and anything else you give them.
"Little things lead to big things."
Both officers would have been stood down on full pay, Hanlon said.
Last year, The Press revealed a long-serving Corrections officer at Christchurch Men's Prison resigned after being confronted with accusations of corruption.
Corrections investigated allegations he smuggled contraband into the prison in exchange for cash or other items of value.
A complaint was later made to police about the matter. They have yet to lay charges.
The Kowhai Unit is a 60-bed medium secure unit for inmates at Rolleston Prison with serious drug and alcohol abuse and dependency problems.
- The Press