Assaults on prison guards by inmates have increased by more than 100 in the last year.
But the Department of Corrections say that a three-year staff safety plan will "directly contribute to making prisons a safer environment".
The Department of Corrections Annual Report was released at 4pm today and revealed that in the 2015/16 year just under 20 staff were seriously assaulted by inmates while on the job, and more than 450 minor and non-injury assaults were also reported.
In 2014/15 there were less than 10 assaults on staff classed as serious and just under 400 minor or non-injury incidents were recorded.
The report comes two days after three Corrections officers were assaulted - one of them seriously and requiring hospital treatment - by a group of prisoners at Auckland Prison.
The report, signed off by Corrections chief executive Ray Smith, revealed that the prison population has more than doubled since 1996.
Back then just 4079 people were incarcerated in New Zealand, compared with 9798 as of September this year.
As a result of that increase assaults on staff had also risen.
Better reporting of incidents by staff had also contributed to the increase.
The rate of prisoner-on-prisoner assaults remained about the same, with 45 incidents regarded as "serious" occurring in 2015/16.
Most of the assaults in prisons are gang connected.
"Prisoners with gang affiliations were said to commit a disproportionate number of assaults in prisons," Corrections confirmed.
"In 2015, gang affiliated prisoners were responsible for just over half - 55 per cent - of assaults despite comprising 29 per cent of the prison population."
Corrections bosses said staff safety was their priority.
"We are working continuously to improve safety and security at all prison sites. Every instance of violence is taken seriously, and we will not tolerate prisoners using violence against others.
"A prisoner responsible for violence will be held to account for their actions.
"While no assault is acceptable, it is an unfortunate reality that they will occur from time to time as we manage some of New Zealand's most difficult and challenging citizens."
The report stated that "Identifying and understanding the drivers for assaults is critical to reducing levels of violence in prisons".
"The Staff Safety Plan increases our potential to predict violence in prisons and improve our capacity to respond through additional staff training and interventions," the report states.
"This plan directly contributes to making prisons a safer environment, through the creation of tools to support the early identification of risks or heightened tensions in prisons.
"Corrections' first priority is to prevent violence... Staff use tools such as the Prison Tension Assessment Tool as an indicator of the level of tension within a prison unit."
Assessing tension in prisons
The PTAT is being trialled at Manawatu and Rimutaka Prisons and in parts of Spring Hill
The tool is designed to help Corrections staff to identify and assess "daily challenges in the overall level of tension" and to ensure that the information is passed on to staff coming on for the next shift.
"The tool works on the basis of a simple form that is completed at the end of the day by unit staff. All forms are combined to generate a wider picture of the situation in each unit," the annual report explained.
"This information is used by unit and site management to take any specific or site-wide actions that are necessary, such as redirection of staff to areas of concern or a reminder at site-wide morning briefings."
Corrections have also introduced violence reduction panels at Manawatu Prison, Spring Hill Corrections Facility, Rimutaka Prison and Northland Region Corrections Facility which focus on "incidents of violence, assaults, bullying and unexplained injuries, in
order to identify and manage perpetrators, protect victims and address bullying hot spots.
"The overall aim is to reduce the number of incidents of violence and bullying," Corrections said.
On-body cameras ordered for prison staff
The department has also tested on-body cameras for staff and the annual report reveals that the trial was a success and 800 units have been ordered for staff.
"The first set of 230 units are received, they will be distributed to eight prison sites," the report said.
"The aim of the trial was to ascertain if wearing the cameras had positive effects on prisoner behaviour and assisted in de-escalating potentially violent situations. Preliminary
results from the trial suggest the cameras reduced the rate of prisoner-related incidents by 15-20 per cent compared to the same period last year.
"The cameras have contributed to a less volatile environment, where prisoners are less likely to use physical attacks."
Corrections said that following a review of the deployment at the eight initial sites, the cameras are expected to be rolled out to all other prisons over the next 12 months.
New stab resistant body armour was also being rolled out.
"By June 2016 all custodial staff across the country had been measured for their new, personal issue SBRA ,' the report stated.
"All eligible staff are expected to have their new SRBA by December 2016. The new SRBA is more lightweight than older versions, and is more suitable for long term use.
All staff are required to wear the armour while on duty.
The prison population at a glance
Every few months Corrections releases information about its prison population.
As of September 2016 there were 9798 people behind bars in New Zealand prisons.
Of those 6.8 per cent were female.
The majority of prisoners were in jail for violent offending with 37.6 per cent of the total population made up of people sentenced on violence offences, followed by 20.1 per cent for dishonesty and a further 20.1 per cent for sexual crimes.
The ethnicity of inmates was mostly Maori, with 4989 inmates followed by 3153 inmates who identified as European, 1108 Pacific Islanders and 466 Asians.
The most common age of prisoners was 20-29, with 3357 inmates falling into that bracket.
There were a further 365 inmates under the age of 16 and 16 over the age of 80.