A Wellington man said to have collected images of child exploitation like some people collect stamps is fighting police moves to give him a criminal record.
The man, who works in IT and is aged in his early 40s, was last year discharged without conviction on 47 charges of possessing objectionable material.
He says he downloaded the objectionable images to satisfy an obsessive compulsive disorder and not for sexual gratification.
Judge Peter Butler decided the consequences of a conviction outweighed the seriousness of the offending and took into account the significant efforts the man had taken to rehabilitate.
But in the High Court at Wellington today, police appealed against the discharge, arguing Judge Butler had erred.
Prosecutor Ian Auld said the judge misapplied the legal test to grant a discharge and didn't properly take into account the level of exploitation in the images.
From a Russian website the man, whose name is permanently suppressed, downloaded images of adults violating children, and children performing sex acts on each other and animals.
"The images in this case were at the higher end of the spectrum," Mr Auld said.
He also cast doubt on the man's explanation for his offending, noting Google search records that inferred the man was seeking out other objectionable material.
Mr Auld acknowledged the man's efforts to seek help but asked for convictions and a supervision sentence, saying there was no evidence to suggest the consequences of a conviction would be out of the ordinary.
But the man's lawyer, Mike Antunovic, argued such a move would bring "devastation" to the man and his family.
It would affect his ability to get a job and might ultimately lead to him losing his house and not being able to support his daughters.
The man was today set to start a six-month rehabilitative programme at WellStop, which assessed him as being of low-risk.
Mr Antunovic said the only thrill the man experienced in downloading the objectionable images was collecting the picture before they were removed from the website, "like collecting stamps".
"He wouldn't even look at them again but the important thing for him was to have them in his collection, so that's what makes this a very much exceptional case and very different from the norm," the lawyer said.
"He had a whole lot of problems with his obsessive, compulsive personality traits."
The man had no previous convictions and didn't waste time before pleading guilty.
Judge Rebecca Ellis reserved her decision.