The Labour Party has called for a cross-political party, targeted plan to reduce the prison population by 30 per cent in the next seven years.
Speaking on TVNZ 1's Q+A today Labour's Corrections spokesman Kelvin Davis said: "We need to sit down and say, 'What are we doing, regardless of who's in government, to reduce the prison population?'"
"The more people we throw in prison, the more people have to at some stage come out of prison, and if we throw them in there and if we mistreat them we think that by making conditions really harsh in there that they're going to come out better people - well then we're mistaken," Mr Davis said.
He also said there's a need for the prison system to have a higher involvement of prisoners' whanau in helping to rehabilitate inmates.
"Corrections says it themselves that one of the best ways is to have whanau engagement in the rehabilitation," Mr Davis said.
"They put some real barriers in the way for the prisoners to rehabilitate with their families."
In a report released last Tuesday the Waitangi Tribunal slammed Corrections for failing to keep Maori from a "destructive cycle" of re-imprisonment.
Around 10,000 Maori children have a parent in prison, the report says.
"This presents a grave risk that the impacts of re-offending will reverberate through the generations, creating a destructive cycle."
Corrections boss Ray Smith welcomed the report and said the recommendations are fair.
"I acknowledge that the rate of Maori re-offending is unacceptable and presents an extremely serious issue for New Zealand".
"This is not something we have shied away from. We have come a long way in tackling what is a complex issue, and I know that all Corrections staff, in conjunction with our justice sector colleagues, are determined to continue their focus on reducing all re-offending and to make our communities safer," he said.