A Dunedin judge has warned a teenage he faces a tough time in prison, while sentencing him to more than two years' inside for the possession and distribution of child abuse images and videos.

The 19-year-old second year University of Otago student has Asperger's Syndrome.

He was sentenced in the Dunedin District Court today to two years' four months' in prison on a representative charge relating the the trading of thousands' of images.

The charge relates to a period between 2013 and the middle of last year, however his lawyer, Anne Stevens, says the teen's interest in the images begun a number of years earlier.

She says if it had been discovered earlier it would have been a matter for the Youth Court, not the District Court.

The summary of facts describes how, in the middle of last year, an anonymous member of the public reported a post the man had put up on an internet forum to the United States National Centre for Missing and Exploited Children.

The post attempted to lure underage girls into sending him photographs.

The US organisation identified the post as coming from New Zealand and passed on the information to our Department of Internal Affairs.

This triggered an investigation during which a Department staff member posed as an adult interested in child abuse images messaged the man.

The 19-year-old then sent the investigator a file which included a number of images and videos of children being abused.

The young man's lawyer Anne Stevens told the court, he was a chronic collector due to his Aspergers.

"For him the abuse images were like baseball cards or marbles."

But Judge John Macdonald didn't completely buy that theory, saying "with images like these there has to be an element of sexual gratification."

The summary of facts also documents content the 19-year-old had stored on his iPhone.

It ranged from abuse of near newborn children to adults.

Ms Stevens told the court he wasn't "into" all the images he had but "kept some because he knew he could trade them for others."

"He also didn't keep duplicates and was quite careful about organising his collection."

When questioned by the Department of Internal Affairs the young man fully admitted his offending, saying he would frequently send and receive images with other members of internet forums.

Anne Stevens argued he should be given a sentence of home detention, saying his condition hinders his ability to feel empathy and relate to the victims of the crime.

But Judge Macdonald said he should have been able to connect the dots and realise what he was doing was wrong.

The man has been granted permanent name suppression.

As he was lead away by a police officer, the distress of his family could be clearly heard at the back of the court.