There were no real children depicted in the files, which were all "computer-generated images, cartoon strips, or comics".

The man, who is in his 50s and cannot legally be named, pleaded guilty in the ACT Magistrates Court on Thursday to one count of possessing child abuse material and two counts of accessing it.

Federal prosecutor Amy Macdonald withdrew several other charges.

A summary of agreed facts shows the ACT Joint Anti-Child Exploitation Team became aware of the offender's illicit online activities when his IP address was identified as having accessed child abuse material on a network called "eDonkey".

Officers raided the man's home in August last year, seizing five electronic devices including a laptop and tablet.

Analysis revealed 21,149 objectionable files, which were mostly pictures but also included hundreds of videos.

"The [child abuse material] possessed by the offender is all computer-generated images, cartoon strips, or comics," the agreed facts say.

"No real children appear in the material."

Chief Magistrate Lorraine Walker on Thursday committed the offender to the ACT Supreme Court for sentence.

The man, who is on bail, will have his case mentioned there for the first time on June 24.

Each of the three charges carries a maximum penalty of 15 years behind bars.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: