The number of prisoners who have committed suicide while in custody has more than doubled compared to last year.
Figures from the Department of Corrections show that 10 prisoners took their own lives while in custody in the past year, up from four the year before.
There were also 26 attempted suicides or self-harm cases.
Minister of Corrections Judith Collins said the increase reflected what was happening in the wider community, with about 600 people recorded as dying by suicide in 2015/16.
She said many prisoners entered the system with appalling mental health and addictions.
Ms Collins said the mental health of prisoners was taken very seriously, and Corrections had put aside $14 million to improve the mental health of prisoners.
Where to get help:
Lifeline: 0800 543 354
Suicide Crisis Helpline: 0508 828 865 / 0508 TAUTOKO (24/7). This is a service for people who may be thinking about suicide, or those who are concerned about family or friends.
Depression Helpline: 0800 111 757 (24/7)
Samaritans: 0800 726 666 (24/7)
Youthline: 0800 376 633 (24/7) or free text 234 (8am-12am), or email email@example.com
What's Up: online chat (7pm-10pm) or 0800 WHATSUP / 0800 9428 787 children's helpline (1pm-10pm weekdays, 3pm-10pm weekends)
Kidsline (ages 5-18): 0800 543 754 (24/7)
Rural Support Trust Helpline: 0800 787 254
Healthline: 0800 611 116
Rainbow Youth: (09) 376 4155
If it is an emergency and you feel like you or someone else is at risk, call 111.