The number of prisoners on preventative detention has soared to 269, the chairman of the New Zealand parole board has revealed.
Judge Sir David Carruthers said only 16 of these preventive detainees - given an indeterminate sentence, imposed on highest-risk offenders to stop them committing a crime - were on parole.
This compared to life sentence prisoners of which there are 216 on parole. There are currently 400 murderers in New Zealand's prisons, he said.
He also revealed the prison muster, as of today, has soared to 8892, the highest it has ever been, which he said was ''a crisis.'' Of those 584 are women.
New Zealand's rate of imprisonment is now 200 for every 100,00 - higher than Malaysia, Czech Republic, the UK, Canada and Hungary. Just one of the ''PD'ers'' is a woman, he said, addressing delegates at the annual Prison Fellowship New Zealand conference.
''The great problem about preventive detainees - who are very often child sex offenders and very unpopular for that reason - is that is almost impossible to find stable accommodation for them.
''Frankly, they are not wanted and when we have released people they have been outed, the release undermined, and returned to prison. No-one feels particularly sorry for them.''
He said the number of those on PD was increasing in number and each was costing the tax-payer $100,000 for every year they were locked up.
The longest serving prisoner on PD is 74 and has spent over 40 years in jail, he said.
''Now that just seems to me to be a terrible waste. And his life, and the life of some of these other long-servers needs to be looked at to see what we could have all done better.''
Christchurch recidivist paedophile Alf Vincent, was sentenced to preventive detention in 1968 after being convicted on seven charges of performing indecencies on five boys aged 12-14, including two brothers, over about a year. He had a string of indecency convictions spanning the previous five years.
In 2009 the Parole Board postponed his next parole hearing for two years, meaning he could not seek freedom until 2011.
Sir David would like to see halfway houses introduced in New Zealand. The houses allow prisoners to re-integrate to society under supervision had proved particularly successful in Canada, he said.
''There is a common sense about it,'' he said. The release from prison can be ''quite frightening'' and many inmates were institutionalised. Halfway houses allowed offenders to take back responsibility for their lives, he said.
One of the things that keeps him awake at night is ''not those who have been released, it's those who we do not release.''
''It is just as much a failure for us to release someone who is goes on to offend again as it is to not release someone who ought to be back with their whanau contributing to the lives of this country.''