A new report has prompted the justice sector to stump up $14 million for offenders with mental health issues.
The Corrections study found 62 percent of prisoners had some sort of mental health or substance disorders, which often went undetected.
"In the past we have dug deep into our own pockets to fund what we can," says Bronwyn Donaldson, director of offender health at Auckland Women's Corrections Facility.
"This funding now acknowledges that we need to put more money in."
Compared to the general population, the Corrections study found prisoners were three times more likely to have a mental disorder and 13 times more likely to have a substance use disorder.
It also found prisoners were four times as likely to have ever attempted suicide.
The Rural Canterbury Public Health Organisation treats 160 prisoners a year, but that's just scratching the surface.
"I'm just glad to see that's been boosted and rolled out to a greater degree," says clinical psychologist Paul Wynands.
He says he often doesn't see a prisoner until they are at crisis point, but this extra funding will allow more prevention work.
"We do expect a reduction in violence, we do expect that people won't escalate into suicide because we'll have been able to deal with their problems earlier on," Ms Donaldson says.
The report found disorders were often undetected and under-treated, but it suggests that integrating mental health and substance use treatment would improve health and reduce re-offending.