A Serco prison guard is under investigation following claims he was involved in a jailhouse fight with a Mt Eden Prison inmate.
The Government was forced to take control of the privately run jail last month when evidence of assaults and contraband emerged.
Amateur videos of prisoners pummelling each other have left Serco badly battered and under investigation.
Now a potential knock-out blow – a claim one of their own, a guard, has been fighting it out too, with an inmate.
"It's just such a mess," says Labour Corrections spokesperson Kelvin Davis. "The whole Serco experiment has failed and they just have to be kicked for touch."
Footage was taken by prisoners, but 3 News understands the prison officer was caught on CCTV footage.
"This isn't just a one-off thing you get roped into during your lunch break," says Mr Davis.
This latest twist has authorities ducking for cover.
Serco refuses to provide details of when and how this latest allegation came to light or if any other prison guards are involved. But it says it has zero tolerance for violence and the guard has been suspended pending a disciplinary hearing.
Serco and Corrections both say the prison is already under investigation and this latest claim will be part of that review.
"They haven't had a grip on what is going on," says Mr Davis. "To me that is wilful blindness."
A spokeswoman for the Minister of Corrections says he's aware of a number of allegations and is waiting on the results of the current review.
"It is whether you can trust what is being looked into and whether they are looking at all the evidence," says Mr Davis.
Meanwhile, Auckland police say as far as they are aware, this latest allegation hasn't been referred to them.