Matthew Bryan McLaren, 31, appeared in the Oamaru District Court last week, where he was jailed for 26 months.
He earlier pleaded guilty to four charges including a charge of manufacturing firearms, which represented five guns he 3-D printed between June 2022 and June this year.
McLaren also admitted manufacturing a restricted weapon, possessing a restricted weapon and possessing ammunition.
New legislation was passed in 2020 making the crime of manufacturing punishable by up to 10 years’ imprisonment.
The court heard that on July 1, police were at the defendant’s home investigating an unrelated matter.
Circumstances led them to execute a warrant-less search for cannabis.
The defendant was in his sleepout and in a conversation with police, said he had a loaded gun on the floor inside.
They also found 26 bullets, 178 3-D-printed parts, a 3-D printer and various tools, springs and barrels used to manufacture firearms.
McLaren was arrested. He told police he was a "firearms enthusiast" and had printed about five other guns in the past two years.
Counsel Katherine Henry said her client struggled with social interaction and enjoyed "tinkering away".
"His hobby was something that he could afford to do ... quietly by himself in his own space.
"It turns out that it’s actually illegal."
The patterns to print the parts were freely available online, the court heard.
Ms Henry said the weapons were not functional in the long term because they were made of plastic.
She emphasised there was no evidence of McLaren being involved in any other crime or distributing the weapons.
"Yes he’s guilty, but not to the nefarious extent that is being submitted by police," she said.
Police prosecutor James Collins highlighted the unique danger 3-D-printed firearms presented to the community.
"When they come into existence they don’t come from the normal channels; they come out of thin air," he said.
He was concerned the weapons would be hard to trace once circulated in the community.
Mr Collins did not accept that McLaren was unaware of the law.
"If he didn’t know, it was through a lack of wanting to know, not through innocence," Mr Collins said.
"To describe it as a hobby probably is a little bit of an undersell. I would describe it more as a pursuit."
He said it was the first sentencing in New Zealand for the charge of manufacturing a firearm — although people had been sentenced for attempting to manufacture firearms.
Judge Dominic Dravitzki agreed there was "huge concern" over this offending becoming more accessible.
"There is obvious and real potential to undermine an effort to remove illegal firearms from the community if the kind of offending you’re involved in becomes more widespread," the judge said.
"There’s particular concerns about firearms of this type not being detectable."
He said because anyone could get hold of the weapons without licences they were "particularly suitable for use in illegal activity if they fall into the wrong hands".
Judge Dravitzki pointed out McLaren had a previous conviction for aggravated robbery and prior gang involvement, but had since reformed.
The judge made a firearms prohibition order which prevented McLaren from using, accessing or being around firearms for up to 10 years.
