Additional staff have been brought in to Mt Eden prison since Corrections stepped in to run the jail last month, the department has confirmed.
However, Serco is being urged to pay for more staff before it once again takes over management of the prison.
Corrections took over the running of the jail, after private operator Serco came under fire following a series of incidents over the last few weeks.
Yesterday, the Corrections ran into problems, when an inmate was discovered dead in his prison cell.
The prisoner, 63-year-old Liberty Charles Baker, was due to be sentenced in the High Court at Whangarei this week after pleading guilty to nearly 80 charges including rape, sexual violation, assault, kidnapping, threatening to kill and grievous bodily harm.
A post-mortem examination was scheduled for tomorrow and Baker's death has been referred to the coroner. A review by the Corrections Inspector was also underway.
Responding to reports of the inmates death, Corrections Association President Beven Hanlon said the department had increased staff numbers at the jail in recent weeks, Newstalk ZB reported.
Staff had been brought in from other prisons across the country to help during the day. As the other prisons also needed staff, a very low number of Serco staff remained on duty during the night, he said.
Current staff were happy to have extra help on board, Mr Hanlon said.
However, there were concerns about what would happen when the prison was handed back to Serco, as the operator's contract was set at a level where it could not afford to employ more staff.