Gang members are engaging in organised fights inside Mt Eden Corrections Facility, filming it on contraband mobile phones, and have somehow posted the footage to YouTube.

The videos were posted to YouTube under an account showing Black Power gang members engaging in organised one-on-one combat sessions in cells and exercise yards.

I'm shocked, I'm stunned by it. I just can't see how this sort of thing can happen in a prison without management knowing about it. - Criminologist Professor Greg Newbold

Large groups of inmates are seen crowding around to watch the bouts and some of the fights last several minutes with no interruption from prison authorities.

Combatants are seen delivering crushing punches and kicks, with some dazed and even knocked out in the vicious bouts.

Six videos have been posted since June 16, with the most recent going up just over a week ago on July 4.

Clothing worn by some of the inmates is printed with "SERCO MECF", suggesting the fights are taking place at Mt Eden Correctional Facility in Auckland.

The worst thing is this whole thing happened uninterrupted. - Criminologist Professor Greg Newbold

Mobile phones are not allowed in prisons, and it is not known how the footage had made its way to YouTube.

Criminologist Professor Greg Newbold, of the University of Canterbury, called the footage "shocking, disgraceful, unforgiveable".

"It's bloody bad news and it should never happen," he said.

"The worst thing is this whole thing happened uninterrupted."

A seemingly organised fight erupts in one of the prison's cells Source: 1 NEWS

He said for the fights to take place without any staff intervention is "disgraceful".

"It shows management breakdown, when inmates can stage these types of events without any knowledge of the staff, or any intervention, it shows the staff aren't doing their jobs and ultimately the responsibility lies with management."

The firm responsible for the day-to-day running of the prison is Serco - a UK firm contracted by the Department of Corrections.

<p>I have commissioned a thorough investigation which will examine these incidents.</p> - Serco director of operations Scott McNairn

Serco director of operations Scott McNairn told ONE News in a statement that fights in prison and the smuggling of phones was illegal and unacceptable.

“I have commissioned a thorough investigation which will examine these incidents. We will work with the Department of Corrections on any necessary actions arising."

He added Serco was in contact with the police, and the company has implemented additional security measures, while access to the exercise yards have been further limited.

“For many prisoners, violence is the norm. We have work and education programmes to address this behaviour, but remand prisoners, about 80 per cent of those we hold, are not obliged to take up these opportunities."

He said 27 mobile phones and 22 SIM cards have been detected so far this year being smuggled into the prison.

In 2012, Serco failed to meet performance targets at the Mt Eden facility - three inmates were wrongly released, three were wrongfully detained and one escaped - and Serco received a six-figure fine from Corrections over their poor performance in managing the prison.

Serco also runs the recently-opened, 960-bed facility at Wiri in South Auckland, as well as providing services in defence, health, education, immigration and other sectors.

The use of cell phones in prison is prohibited and internal charges or police charges could result. - Corrections northern regional commissioner Jeanette Burns said.

In a statement to ONE News, the Department of Corrections said an investigation will be launched into how video footage of prisoners fighting inside Mt Eden could be posted on social media.

“As part of its initial response MECF will be increasing its frequency of searches for contraband, including cell phones, and changes will be introduced to strengthen the structure around how prisoners are monitored during the periods they’re out of their cells,” northern regional commissioner Jeanette Burns said.

“The use of cell phones in prison is prohibited and internal charges or police charges could result.”