Six people have appeared in court today, charged over allegations Corrections staff were bribed with cash and sex to take contraband into Wellington's Rimutaka Prison.
Of the six, three men have been charged with accepting money to bring in contraband, while a 50-year-old man is accused of accepting sex from a 37-year-old woman.
The woman is charged with bribery, and a current Rimutaka inmate is allegedly a party to offering the bribe.
Corrections chief custodial officer Neil Beales told Checkpoint he believed contraband such as drugs, tobacco and cell phones, were being brought into Rimutaka prison.
"I would like to think that hopefully, once all of this is resolved, it will put a lid on what has been going on for quite some time and it will resolve a lot of issues for the vast majority at Rimutaka who have had zero involvement with this and just want to get on with their jobs."
However, the investigation did have some lessons, he said.
"Once the court cases and the charges have progressed the way that they will do, we need to take lessons from this to see what improvements and what strengths we can add to prevent similar recurrences."
Staff needed to feel safe to raise issues if they felt their colleagues were not behaving in a professional or "perhaps even criminal" manner, Beales said.
"We want a system that works for all" - one that would catch and stop anyone trying to exploit vulnerabilities within the system, he said.
Beales said the ongoing investigation was looking into how staff complaints were handled.
"We need people to feel they can go right to the top if they need to be, and then you need to have open communication and not have systems that are so closed off that people feel unwilling or scared to raise issues."
There were a lot of moving parts to running a prison, he said. There were 9000 prisoners in 18 jails around the country, one of them being private. There were 10,000 staff, and Corrections worked with about 30,000 people in the community.
"It's not a perfect system.
"We are constantly reviewing our processes., looking at upgrading our electronic monitoring, our CCTV, making sure that we've got good searching processes in place at our jails, where we've got X-ray machines, making sure that we stick rigorously to our processes.
"Nobody comes into a prison without being properly searched. But again, the items that can come in can be small, small quantities of drugs or large items like cell phones or even bigger."