Corrections will not confirm whether John Vogel will receive compensation but continue to defend that the decision for him to be in solitary confinement was his own.
The Corrections Department acknowledged convicted murderer Vogel was kept in solitary for longer than the statutory maximum period, but that he had requested it.
Vogel was serving a life sentence for murder in 2000 when he pleaded guilty to three prison disciplinary charges relating to his drug use, a Corrections spokesperson said.
The spokesperson told NZ Newswire that Vogel appeared before a Visiting Justice for sentencing, and the prisoner himself requested a period of cell confinement of 21 days to be imposed.
This was in excess of the statutory maximum of 15 days.