A child sex offender was paid $26,600 in compensation by the taxpayer under a scheme which has awarded more than $500,000 to prisoners since it came into effect in 2005.
But less than half the money - which is paid mostly for administrative bungles that result in inmates being released too late - has been handed over to the prisoners because of a long-running row about whether their victims should be paid first.
Figures obtained under the Official Information Act show sex offender and aggravated robber Patrick John McGreevy was paid the fourth-highest amount to an inmate - $26,598.50.
The biggest payment of $43,313 has been held in trust since 2007 for violent gun-wielding kidnapper Steven Brent Gunbie.
He will get the money only after any claims from victims of his crimes are settled.
However, only six victim claims have been successful since the scheme started in November 2005.
The Government has now made the scheme permanent even though its own advisers say it does the least possible for victims of crime.
The latest version of the scheme was opposed by victims' advocate Garth McVicar of the Sensible Sentencing Trust and human rights lawyer Tony Ellis, regarded as having won some of the most significant court victories for prisoners' rights.
The six victims have received payments totalling $49,000, and another $63,000 is being held in 19 cases for court-ordered reparation.
Prisoners have received $220,000 from a total pool of $516,000. Another $290,000 is being held in trust pending 12 claims from victims.
The scheme came into being after some prisoners at Auckland Prison at Paremoremo were forced under a programme called the "behaviour management regime" to live in isolated squalor and were treated inhumanely .
Prisoners represented by Mr Ellis won compensation totalling hundreds of thousands of dollars, although the sum was reduced on appeal.
The outcry over the initial award met a surge of outrage over the rights of victims of crime, leading to the Labour government introducing the law.
After the initial payments, almost all compensation payments are being made for administrative bungles which keep people in prison beyond their release dates.
Corrections Minister Anne Tolley said work was in progress to move to an electronic system to reduce the number of errors.
"It's not good enough, and one miscalculation is too many.
"Corrections assured me that they are working with Courts to tighten up procedures, and improvements are being made.
"It's a very complex system, but taxpayer money shouldn't be going to prisoners because of any errors."
A spokeswoman for Justice minister Judith Collins said she believed claims now being processed would push the amount higher.
Corrections deputy national commissioner Maria McDonald said "wrongful detention ... refers to situations where a person has been detained in prison beyond their correct statutory release date".
"Sentence calculation is a complex and technically difficult task which is performed by receiving-office staff in our prisons and based on information received from the Ministry of Justice.
"They carry out this task in respect of tens of thousands of prisoners being received into prisons each year."
A spokesman for the Ministry of Justice said it had tried to reduce the number of errors by sending copies of judges' sentencing notes to Corrections as a safety net to information recorded at the time of sentence.
Mr McVicar said it was a "Mickey Mouse" scheme under which victims of crime had to re-engage with offenders if they wanted compensation.
"Victims don't want to have any involvement with offenders ever again."
He said the law was a response by Labour to an outcry over payments of taxpayer money to criminals at the same time the trust was raising concerns about treatment of victims.
The Justice Minister at the time, Phil Goff, "was trying to pacify and tried to have a foot in both camps", said Mr McVicar.
Current Labour Party justice spokesman Andrew Little said the law did not work and failed to meet victims' needs. The number and value of payments to victims showed it had failed.
It also had the perverse effect of victims benefiting only when the state abused the rights of a prisoner.
"Whether we can help victims is dependent on whether or not we hurt prisoners."
Ms Collins made the scheme permanent in legislation passed by Parliament this month.
She said it "ensures offenders will not receive compensation for wrongful treatment while in custody, without first having to repay the debt they owe for the harm they caused to their victims".
1. $43,313 - Steven Brent Gunbie
Convictions include: Kidnapping, firearms
2. $30,938 - Alistair Wayne Robinson
Aggravated robbery, theft, burglary
3. $27,000 - Shannon Quinton Watene
Possession of firearms, presenting weapon and serious assault
4. $26,598 - Patrick John McGreevy
Aggravated robbery, child sex offender
5=. $25,000 - Tiana Jacqueline Condon
Drunk driving (4)
5=. $25,000 - David William Wild
5=. $25,000 - Te Awa Jason Greg Wilson
5=. $25,000 - Maree Dawn Guest
9. $24,750 - Matthew George Kidman
Aggravated robbery, other violence charges
10. $20,000 - Daniel Michael Katipa