As we know that the cost of keeping someone in jail has reached $100,000 per annum, these 1800 extra prisoners are going to create ongoing government expenditure of $1.8 billion on top of the one-off billion-dollar cost of constructing the new buildings.
This turn of events is a tragedy whichever way you look at it.
New government spending of this magnitude generates a huge opportunity cost as it crowds out the much needed investment in schools, hospitals, police, the environment and so on that is being driven by teeming immigration driving population growth.
New Zealand's shamefully high rate of incarceration looks like getting even worse.
Though the Corrections officials with whom I regularly interface have been deeply and, I would have thought effectively, committed to the goal of reducing re-offending by a quarter by next year, this goal will not be reached.
Re-offending is what makes New Zealand's prison muster so large.
When compared with places like Australia with an incarceration rate which is about two thirds of ours, we don't have longer sentences nor do we have a larger range of offences which attract a prison sentence.
What sets us apart is our sky-high rate of reoffending - so the target adopted by Corrections is the right one, but the growing prison population has meant that the resources have not been available to meet that target.
A Howard League literacy tutor sent this description of just how reoffending comes about. You can bet that this story is repeated hundreds of time every year:
"My first student was released about three months ago, and is now back in prison. He was released with the condition that he see his probation officer weekly and that he take on some training. I volunteered to continue lessons with him. I only saw him once, despite setting up appointments. I phoned him a few times and he said it was too hard; he had no money and all sorts of family problems so he didn't have time or energy to continue lessons. He was clearly distressed, and probably had family and friends putting pressure on him to break his good intentions. He has a learner driving licence but was picked up several times by police for driving offences, so has come back to prison with fines and demerit points..."
This lack of support for vulnerable released prisoners is endemic in New Zealand and if you examine countries with much lower rates of reoffending you discover that far more attention is paid to prisoners after their release.
In Britain, for example, the local Howard League is funded to provide Bail Houses. These are halfway houses where released prisoners are accommodated, given help with finding employment and general reintegration back into normal society.
This kind of treatment is not needed for every released prisoner as many have supportive families to return to but some do need this level of help which, in New Zealand, just doesn't exist.
Our tutor summarises what she has seen thus:
"What is really irritating is that he is quite bright, and had he actually gone to school regularly from the age of 5 he could well not have ended up in prison. What makes me angry is that he should have had more support to help him when he was released at a really vulnerable time, and a crucial point between returning to criminal ways, and being able to take a different path."
Reducing re-offending requires a number of strategies.
Overseas, the two keys to big reductions in reoffending are giving prisoners basic skills while in jail and getting them into paid employment on release.
The government which finally picks up the burgeoning cost of prisoners must focus even more on literacy and work skills.
If getting a driver's licence while in jail were possible, many more released prisoners would get jobs.
It's not rocket science!
Mike Williams grew up in Hawke's Bay. He is CEO of the NZ Howard League and a former Labour Party president. All opinions are his and not those of Hawke's Bay Today.
