A former Corrections officer says corruption at Rimutaka Prison is widespread and she was threatened with the sack when she spoke up.
A three-year police investigation into the jail has led to one prisoner, a current employee, three former workers and a member of the public facing charges of corruption and bribery.
The prison guard, who RNZ has agreed not to name, worked at Rimutaka Prison for seven years and said the charges laid under police Operation Portia would not stamp out corruption.
She said guards walked past cells and turned a blind eye to contraband, including mobile phones and tattoo guns.
"They're just trying to pretend they're not seeing things that are going on right in front of them."
However, it was not just prisoners in possession of banned items; some staff would also bring in banned items without the proper paperwork and security clearance, she said.
The former officer said she had taken contraband memory sticks off staff as they came through the gates to work. She handed them to the security manager, then watched as he gave them back to the staff.
"That was one of the units that was full of mobile phones and contraband, and that was while Operation Portia was going on."
She said there may have been information on the memory sticks which would have been useful to the investigation, but they were never given to police.
Corrections described its current and former staff who were charged in relation to Operation Portia as a small group, saying the majority of its employees acted with integrity.
However, the former guard disagreed, and said there needed to be an overhaul of managers from the top of the organisation.
"Even though Operation Portia has finished, they've no way near dug out as many staff that are corrupt that they need to, it's still ongoing."
She said when she tried to raise concerns, she was told she was being too strict.
"Every time I tried to do my job I just got shut down as though I was stupid," she said.
"They just sweep it under the carpet still, and it's too big for people that are genuine and that want to do the job correctly ... there's too much corruption."
The former guard said at one point she was told she would get the sack if she filed any more incident reports.
"That came from my manager and he's still working there today."
She put the "softly-softly" approach to staff corruption down to fears of being labelled a troublemaker and disrupting the peace.
"I think everyone just wants to be a 'yes' person because that's the only way you're going to work up in Corrections ... if you don't, then you're going to not keep your job."
The former guard said she had worried about being set up by her colleagues, and had spoken to other staffers who had left because of the culture of bullying. She had put in a personal grievance against another guard in the past and said she left under a cloud.
"I just got to the point that because there's so much corruption going on, I don't feel safe ... now I've left, honestly, I feel like a different person. Like the weight has just been completely lifted off my shoulders."
The prison guard union said its members had raised concerns about staff conduct at Rimutaka Prison, before the police investigation. Corrections Association president Floyd du Plessis said most staff were not involved, and a small group had brought the wider prison guard cohort into disrepute.
Corrections expects staff concerns to taken seriously - Beales
Corrections did not respond to RNZ's questions about the former guard's claims, but chief custodial officer Neil Beales said in a statement that staff were constantly trying to stay one step ahead of inmates.
"Prisoners will often go to extreme lengths to continue offending while in prison. Our staff manage around 9000 prisoners, who are some of New Zealand's most dangerous people and can be highly manipulative and threatening."
He said the Rimutaka Prison director was focused on changing staff culture, standards of behaviour and professional practice - work that started in 2021, the year after Operation Portia began. Those changes included encouraging staff to speak up about concerns and increasing accountability.
"My clear expectation is that if someone raises concerns about a staff member's integrity, it's taken seriously. If any staff member feels their concerns have not been taken seriously, I urge them to contact me directly. We will not stand for dishonest or illegal behaviour."
The integrity training provided to new prison guards would be reviewed next year, Beales said.
Rimutaka Prison was last inspected by the prison watchdog about a fortnight ago, but the Office of the Inspectorate would not release its report until next year.