The Department of Corrections has denied media reports that overcrowded prisons are influencing policing decisions.
New Zealand's prison capacity is back in the spotlight after a leaked email to the Herald on Sunday showed police officers in Wellington were told to "carefully consider" whether to make arrests, as Remutaka Prison was almost full.
The email said: "Repeat breach of bail and warrant offenders may be remanded in police custody for a prolonged period. Arresting officers should consider this before making an arrest."
But the Department of Corrections has denied this and said there is enough capacity to manage anyone police decide should be remanded in their custody.
Corrections said Rimutaka Prison has 750 beds for prisoners with 61 currently vacant.
Prisons in New Zealand can currently house up to 9020 inmates, that's down from the usual 9561 because they haven't got enough staff. There are currently 583 prison beds vacant around the country.
Corrections acting national commissioner Leigh Marsh told AM on Monday he's not sure why police would send an email saying officers needed to "carefully consider" whether to make arrests.
He also said he's not aware of any correspondence from his office or the local prison to indicate that Remutaka Prison has reached capacity.
"I don't want to comment on police practices and we can't control the emails they send themselves, unfortunately, but no, it's not near capacity," Marsh told AM co-host Ryan Bridge.
"The reality is if someone needs to come to prison, they can come to prison. We've got plenty of space."
Marsh said police need to make "smart decisions" around who they arrest but said they have plenty of space in prisons.
A corrections officer working in a New Zealand prison emailed AM saying they're "really worried" about the lack of staff and the safety of the prison they're working in.
The officer also raised concerns about continued assaults on corrections staff members including an attack last weekend.
Marsh told AM he's aware of "some incidents" over the weekend.
"Nothing's come across my desk today, but I'm aware there have been some incidents over the weekend, but no assaults are welcome in our sites. It's not good enough for that to happen," he said.
"We're doing a significant amount of work, partnered with our unions. We're looking at multiyear investments around tactical communications, better equipment, better training for our staff to try and keep them safe."
Marsh told AM he hasn't seen a massive increase in staff assault numbers but said they "ebb and flow".
"I think there are periodic monthly spikes. As I say, no assaults are welcome in our sites at all and it's not acceptable," he said.
"But these things happen unfortunately, it's a prison environment and we deal with some very difficult and dangerous people. The best thing we can do is try and keep our staff safe with the best training and the best equipment."
The president of the Corrections Association of New Zealand Floyd Du Plessis told AM just because beds are available doesn't mean there is enough staff to accommodate them.
"From our perspective, there's no question we cannot currently safely man the prisons and that's evidenced by the fact that even though right around the country we're running special emergency rosters to try and manage the short staffing," Du Plessis said.
"We're not managing, we're not running minimum entitlements, we're not giving visits, we're not running rehab programs. So what we're having is a breeding ground of crime."
Du Plessis warned with the current staffing shortages, criminals are being released back into the community worse than when they went into prison.
"They're not being improved, so we're releasing these people back into the community worse than they were before and that's what's driving that increase in crime," he said.
"Unfortunately, unless we do something to drastically increase the staffing numbers, it's something we just cannot improve on."
Marsh said assaults on corrections staff members are a "regular occurrence" and it's "not good enough".
"One assault that I'm aware of over the weekend, where a staff member was assaulted in a unit and ... in this particular instance, it seems the only reason the staff member wasn't severely assaulted was due to a prisoner stepping in and helping," Du Plessis said.
Corrections Minister Kelvin Davis told AM in a statement it's not correct that prisoners will not be able to be housed safely if they need to be in custody.
Police did not deny the email was sent to police staff when asked by AM.
Watch the full interview with Leigh Marsh and Floyd Du Plessis in the video above.
