Police have charged six people in a three-year investigation by the National Organised Crime Group into suspected criminal activity at Rimutaka Prison.
The accused are a prisoner, a current employee, a member of the public and three former employees, aged between 37 and 50.
They are charged with alleged offences involving corruption and bribery, which required Attorney General consent to prosecute, police said.
The six were from Auckland, Porirua, Hutt Valley and Hawke's Bay and would appearing in the Hutt Valley District Court on Tuesday.
Operation Portia began in 2020 following Operation Dory, a drug-related investigation at Rimutaka Prison.
Those involved in Operation Dory have already been before the court, police said.
During the course of Operation Portia, police interviewed almost 200 people, including Corrections staff, prisoners and other witnesses.
The investigation involved tactics like the interrogation of phones, bank data and viewing hours of CCTV.
In addition to the corruption and bribery accusations, Operation Portia investigators identified alleged offences involving assault and one case of using a document.
These investigations were undertaken by Wellington District Police staff and resulted in five people being charged. Four have been dealt with by the court and one prosecution remains ongoing. These investigations and those held responsible are separate from the corruption and bribery charges laid as part of Operation Portia.
Police worked closely with Corrections and both organisations were committed to working towards preventing corruption and other criminal offending, police said.
Corrections' National Commissioner Leigh Marsh said the department would not not tolerate illegal behaviour in its prisons. "We expect a high standard of conduct from all employees," he said in a statement.
"We employ around 10,000 staff in prisons and the community. The overwhelming majority of our people act with integrity, honesty and professionalism.
"At Rimutaka Prison, there is ongoing work to strengthen our culture, ensure professional standards of behaviour are consistently followed and maintained."