The Government has charged Serco $8 million to cover the costs of resuming control of Mt Eden Corrections Facility last year.
The Department of Corrections invoked a "stepping in" clause in Serco's contract in July amid concerns of organised violence and injuries to prisoners at the jail.
Corrections Minister Judith Collins said today that the total cost of this action, combined with outstanding performance notices, was $8 million.
She also confirmed that the Corrections Department would continue to manage the prison until the end of Serco's contract in March 2017.
The British-based company would only provide staff at the jail, Mrs Collins said, and would make no profit during this period.