Much of what is happening seems like a shift in styles of control, as people are moved from prison cells to various forms of electronic monitoring, intensive supervision and home detention. Three quarters of the 40,000 people managed by the department are already in the community.
The public face of change is the first ever Māori Corrections Minister, Kelvin Davis. He has a personal stake in the issue, including friends and family among the prisoners. People from his own iwi Ngāpuhi are incarcerated at 10 times the national average.
Now Davis is head of the whole system. And no matter how determined to make fundamental change, the tools at his disposal are various kinds of correctional control.
One favorite alternative is home detention. This is still a form of incarceration. It leaves family and partners caring for people who are stuck inside and unable to work or contribute financially.
The costs of confinement are transferred from the state on to usually poor families, and the burden of care placed largely on women, who serve the sentence alongside the men being detained.
As homes are turned into sites of detention, it raises serious issues about the intrusion of surveillance in New Zealand's most marginalised communities.
Some will insist it is a step in the right direction. And if you ask prisoners whether they'd rather live with their families and raise their children, even with constant surveillance and monitoring, they'd almost certainly say "yes". But it feels a bit like forcing a child to choose between being caned or deprived of dessert as punishment.
It would be naïve not to be suspicious of where these choices lead and what will replace our downsized prison system.
I never thought it possible to reduce prison numbers so sharply just by improving bureaucratic processes. Davis says the changes are still being rolled out nationally and there are more falls to come.
These are real achievements. But lets make sure it's not just an exercise in substituting prisons with other forms of surveillance and control.
• Liam Martin is a criminologist at the University of Victoria.