Judges and lawyers say that probation officers are not writing good enough reports to help judges determine if someone should go to prison.
About 30,000 Provision of Advice to Court reports are written by probation officers each year. They are supposed to tell a judge what they need to know about an offender and recommend a sentence.
However, Criminal Justice Reform Panel chair Chester Borrows said nobody is happy with them.
"We are hearing from judges and from lawyers particularly that they are cut and paste documents using the same phrases over and over again," he said.
"And probably only about a page and a half long which is far too brief for the gravity of the offending and the impact of the likely sentence."
Corrections said a probation officer generally spends about eight hours on the report, and then recommends a type of sentence to be imposed.
If a judge has enough reasons to reduce a sentence below two years, there's a greater chance of home detention, or a good chance the offender will only serve half behind bars.
Mr Borrows said the reports should be specific to the offender and crime and explain the complex reasons behind the offending, but that's not always the case.
"We have also had situations where probation officers have cut and pasted out of siblings of the offenders' reports and even got the wrong names in the reports, which is pretty damning.
"We have now got lower numbers of people appearing before the court than we have had in 30 years, so you would wonder why there is a lack of resource here."
Former inmate Billy McFarlane now runs a programme for high risk offenders in Rotorua, some of whom are awaiting sentencing. He said probation officers often miss out key information in the reports and have actually been incorrect.
"When they wrote in one offender's report, they spoke in there about methamphetamine distribution and I said to the probation officer 'he is not up on methamphetamine charges'," he said.
Mr MacFarlane said the probation officer insisted she was correct before double-checking and realising otherwise.
"That's the level of incompetence that sits inside Corrections and it is not acceptable because we are talking about people's freedom here."
Māori are over-represented in every stage of the criminal justice system, and Mr Borrows said the section in the report that pertains to tikanga and culture is often covered glibly.
Howard League spokesperson Hampton QC said the pre-sentencing reports have turned from in-depth studies to routine 'box-ticking' exercises over the past 20 years, and he's concerned for the judges.
"It is the most difficult task," he said. "Sentencing judges should have the best quality materials in front of them to enable them to fulfil their role and I believe that they don't get that best possible material in front of them now."
Judges have seen a need to call for a specific cultural report and that is because of the inadequacies of the probation officers' pre-sentencing reports, Mr Borrows said.
Mr McFarlane recently wrote a cultural report and said they are essential.
"It is giving the judge a lot more information than what the pre-sentencing reports are giving - they're giving nothing," he said.
"In the same offender's latest probation report they still never spoke about childhood trauma, they still never spoke of the fact that he was sexually abused."
The Department of Corrections refused to be interviewed but said in a statement that judges have raised concerns about the reports and have asked for more information about domestic and cultural circumstances and how a recommended sentence would impact the offender.
Department of Corrections chief probation officer Darius Fagan said they updated a pre-sentencing interview guidelines booklet late last year, and judges' feedback has been positive.
Nationwide training for probation officers was launched late last year too and will be complete next month.