Joshua Dean Mennie, 33, of Coconut Drive, was ordered to serve a minimum of seven months before being eligible for parole when he faced the District Court in Sydney on Wednesday, March 27.

He had pleaded guilty to possessing child abuse material.

Agreed facts presented to the court said Mennie was stopped by police while driving on Illaroo Road, North Nowra, about 7am on November 11, 2009.

He was arrested on other matters that were dealt with in the Nowra Local Court, but police seized three mobile phones - two that were in the car's centre console and a third Mennie was carrying.

Those phones contained more than 187,000 images that were "predominantly of adult pornography" along with photos and videos of Mennie having sex with adults, Judge Christopher O'Brien said while summing up the case.

However among them were 515 child abuse images, including 275 classified as being in the worst category.

While conceding the child abuse material made up "a miniscule proportion" of the pornographic images stored on the three devices, Judge O'Brien said the possession was "very serious".

"Offending of this type occurs on an international level, and is becoming increasingly prevalent and is difficult to detect given the anonymity provided by the internet," he said.

The offending "creates a market for the continued corruption and exploitation of children", Judge O'Brien said.

"The possession of child pornography is not a victimless crime - that is children are sexually abused to supply the market."

During sentencing submissions held in Nowra during February, Mennie's representative Mr Lewis argued there was a "reasonable possibility" Mennie was not aware of the abuse material being on his phones, as they made up such a small proportion of all the images.

"If he had an interest in child abuse material they would certainly have made up a higher percentage of all the images," Mr Lewis argued.

He said that as they were "buried among the rest of the images on his devices" they could easily have gone unnoticed.

Judge O'Brien rejected the claim, saying Mennie's internet history showed he was searching under terms including young, teen, high school, petite and little that could reasonably be expected to potentially access images of children.

In fact at least eight times Mennie was blocked from sites, he said, receiving the message, "Your browser is trying to contact a domain that is distributing child sexual abuse material. Access to this domain has been blocked by your internet service provider in cooperation with Interpol."

Judge O'Brien also noted the images were hidden in password-protected folders and storage areas disguised as legitimate apps.

A sentencing assessment report to the court said Mennie was diagnosed as having ADHD while in year six, and while that issue had largely resolved over the years he started taking illegal drugs while attending schoolies, starting with MDMA before moving to frequent cocaine use.