Leigh Andrew Coghlan, 40, was convicted on 12 charges relating to child pornography in Launceston's Supreme Court yesterday.

The court heard he accessed, possessed and sent the pornography between 2006 and 2012.

Following a covert investigation, the Australian Federal Police raided Coghlan's then Longford home finding more than 1000 child exploitation images and videos on his computers.

Most material fell within the lowest range of seriousness - erotic posing with no sexual activity - while two videos were regarded as the worst example of child pornography containing either sadism or bestiality.

If the child exploitation stories that were also found on his computer were printed they would come to 1600 pages of text, the court heard.

They involved sexual assaults, including drugging, defecation, bestiality and torture by men and women against children of all ages including infants.

"Although the stories and conversations do not (involve actual children) they nevertheless also may have the effect of normalising, encouraging and escalating paederastic behaviour," Justice Robert name Pearce said.

During an online conversation Coghlan said four-to-six-year-old girls were too young to assault unless "the child liked it".

"It's OK but that nine is the best age for penetration," he said.

In addition he had 55 animated or virtual images of children and more than 11,000 non- pornographic images of children showing them urinating, with little or no clothing, wearing nappies or underwear and videos of children in public places.

They did not form the basis for any charges.

A dysfunctional childhood contributed to Coghlan developing multiple paraphilias in adulthood including paedophilia, sexual arousal from wearing and observing nappies and dressing as a female baby, cross-dressing, and urophilia, which is an arousal from urine.

Justice Pearce ordered he serve a maximum of two years and three months' jail.