At least one Hawke's Bay Regional Prison employee is being assaulted by inmates every month, new data suggests.
Between October 2017 and August 2021, 149 assaults on staff were reported at the Mangaroa facility.
The month-by-month breakdown revealed through an Official Information Act request by the National Party shows there was only one month in the past 45 where an assault on prison staff did not occur.
Corrections says it's working to make the job safer for Hawke's Bay staff, including the rolling out of body cameras.
But the union for prison workers says inmates are "laughing in the faces" of prison employees, and has called for tasers to be made available to officers and harsher penalties to be introduced.
Corrections Association President Floyd du Plessis told Hawke's Bay Today that "sadly" the number of assaults were under-reported.
"If all assaults were reported there would be at least a third, if not more, of an increase to that number," du Plessis said.
"At the moment there is an extremely high number of staff being threatened with violence. We classify that as active threats, and these are not reported.
"Threats of physical violence, which often result in actual violence, are also unreported, and all of this has a massive impact on the mental health of staff."
He said there were few consequences for low-level offenders and that needed to change.
"At the moment, they assault an officer, they may or may not get a couple of days lockdown, and they're back and laughing in staff's face.
"They get a smack on their hands, potential lockdown, and that's it."
He said police prosecutions around these assaults were "extremely low".
"We want all assaults on Corrections staff to go to police prosecutions. We also want offenders to have a cumulative sentence as opposed to concurrent.
"We want offenders to have a stand-down parole date for six months."
He said the union supported the idea of tasers being carried by front-line staff and teams.
"Tasers would act as an immediate deterrent, but we also want additional tools for staff to help them protect themselves."
Chief Custodial Officer Neil Beales said the majority of assaults on staff at Hawke's Bay Regional Prison caused no injuries or non-serious injuries.
"Non-serious injuries could be bruising or a bloody nose following an assault, and serious injuries could include broken bones or fractures, through to any form of sexual assault where police charges are laid," he said.
He said work was being done to address this, including a two-year rollout of new on-body cameras to Hawke's Bay.
Beales said the victims of assault were supported by Corrections.
Prisons regularly reviewed assault incidents to determine whether similar occurrences could be prevented in future, he said.
"If there are lessons to be learned these are relayed to staff as part of Corrections' commitment to keep our staff, the people we manage and the public safe."
National's Corrections spokesperson Simeon Brown said Corrections Minister Kelvin Davis needed to make sure staff in New Zealand's prisons "have the resources and support they need to get on top of this problem".
In response, Davis said he had "zero tolerance" for assaults in prison and said offenders should be held accountable.
"While we have reduced the prison population by about 3,000 people since 2018, we are still locking up serious violent offenders," Davis told Hawke's Bay Today.
"This has led to a higher concentration of prisoners who can be volatile and difficult to manage."
He said a culture of reporting every assault, no matter how minor, was being encouraged and had led to higher numbers of these types of incidents on paper.
Davis said a review of safety equipment for staff was part of the action plan to address the assaults, and officers needed the "right tools" to do their job.