Bernd Schnull, 62, of Warranwood, claimed watching child pornography helped to relieve his stress and anxiety over the problems he was having with his wife at home.

Schnull would download the images in his study where you needed an access code to get into the room. He would come home from work and go straight on to his computer.

Schnull pleaded guilty in the County Court on Tuesday to one count of accessing child pornography and one count of possession of child pornography involving children aged from six months to 16.

He faces a maximum penalty of 15 years' jail.

Prosecutor Samantha Holmes told the court Schnull had downloaded a total of 45,287 images and 1611 videos between August 8, 2011, and March 20, 2012.

The police measure child pornography on a scale, with level five being the worst. Schnull had nearly 200 images in the level 5 category.

Schnull was arrested during a joint state and federal police operation aimed at smashing a child pornography ring operating on Australia's eastern seaboard.

He was one of 16 men arrested after police raided 19 properties in Victoria, New South Wales, Queensland and the ACT.

But defence barrister Sandy Robertson said Schnull had been acting alone and did not take part in any chat rooms on child pornography or share any files.

Mr Robertson said Schnull sought psychological treatment after his arrest to try to understand his offending.

He said Schnull claimed to have stumbled across the child pornography and was "caught in a web of depraved vile images".

Schnull knew what he was doing was illegal but watching child porn helped to ease his boredom at home and the lack of intimacy with his wife.

Judge Mark Gamble, who briefly adjourned the plea hearing after being asked by the prosecutor to view a sample of 40 images taken from Schnull's computer, said sexual stimulation must have played a role in Schnull's offending.

Judge Gamble said Schnull had gone to a great deal of trouble to download the images, including securing his study so others could not get in.

Mr Robertson said it was difficult for Schnull to explain but he had been attracted by the novelty of the images and was driven by curiosity.

Downloading thousands of images became a compulsive habit.

Mr Robertson conceded there must have been an element of sexual stimulation for Schnull otherwise he wouldn't have bothered.

Since undergoing therapy in August last year, Schnull, who had had little empathy for the victims, was now ashamed and remorseful and realised his actions had helped feed the market for child pornography.

A psychological report indicated Schnull did not fit the profile of a repeat sexual offender and was unlikely to reoffend.

In his letter of apology read to the court, Schnull said he felt revulsion for what he had done and realised he needed help.

Ms Holmes said Schnull, a father of four, should be jailed for at least 18 months and placed on the sexual offenders register for 15 years given the seriousness of the offending and nature and amount of material seized.

Judge Gamble will sentence Schnull on February 13.