The price of keeping people in jail is rising, even as New Zealand’s prison population is falling dramatically.

Newstalk ZB can reveal that each person behind bars costs around $150,000 a year, which is $30,000 more than the 2018/19 financial year.

The figures prompted the Green Party to call prisons a “costly failure”, while National says the government was good at handing out money with no expectation of results.

Corrections Minister Kelvin Davis maintains that “these are simple calculations, [and] as the number of inmates decreases, the amount of money per inmate therefore increases on average”.

But the Corrections Association questions the value for taxpayers’ money and accuses Davis of being political about prisoner numbers.

Since March 2018, the prison population has fallen by more than 25%, from a peak of 10,820 to 7,677 today.

During the same period, the average cost per prisoner rose from about $120,000 to $151,000, according to National Party calculations based on annual reports from the corrections department.

Data published on Newstalk ZB by Corrections confirms that the total cost of prisons in the country has increased by $140 million since 2018/19, from $1.1 billion to $1.3 billion.

Deputy National Commissioner of Corrections Leigh Marsh defended the increase, saying the overall cost of running a prison has not gone down.

“In the same way that the average cost per person in an apartment situation increases or decreases depending on whether there are more or fewer people in the house, the outgoing costs remain the same,” he said.

He said fixed expenses — such as pitch rental, staff, electricity and maintenance — don’t change immediately.

“We can’t just increase or decrease a prison’s footprint based on the increase and decrease of the prison population.”

Davis said the increase per prisoner was also due to an additional $30.5 million for rehabilitation and reintegration.

“There’s always a cost to doing things differently,” he said.

But National Party corrections spokesman Simon O’Connor said prison rehabilitation programs were not delivering real results.

He pointed to the high rate of prisoner recidivism in New Zealand compared to the rest of the OECD.

“Of those who leave, have they actually received the rehabilitation they want and need? I think the answer for many is no,” he said.

“We are letting these people out, not having received the support that most of us in New Zealand would expect.”

Davis dismissed those concerns, saying many initiatives of the former national government had not worked.

“Alcohol and other drug programs were provided to about 2,000 people every year…these were replaced,” he said.

“There is no point, just for appearances, in pumping thousands of prisoners through very low value programs.”

Corrections Association president Floyd du Plessis said he “completely disagrees” with that approach and suggests Davis was “playing the political game.”

“The one thing he keeps mentioning every time is the prison population…that’s his only measure of success.”

“Unfortunately, if delinquency in the community has increased and violence in prisons has skyrocketed, clearly you haven’t improved anything,” he said.

“Prisons are expensive, it’s a necessary evil… [but] are we getting our money’s worth?”

Justice Greens spokeswoman Golriz Ghahraman went further.

“Prisons are very clearly a costly failure.”

She wants to standardize prisoner rehabilitation programs.

“Community groups…they are doing their best, but we don’t know from prison to prison what a course will entail, who will teach it and if it will be of the same standard as elsewhere,” a- she declared. .

Corrections said a decrease in the number of inmates participating in some rehabilitation programs was due, among other things, to the elimination of lower-intensity programs and a higher proportion of people serving longer sentences or periods of custody.