Leigh Andrew Coghlan, 41, yesterday pleaded guilty to 12 charges of accessing and sharing child pornography. 

For more than five years until 2012, Coghlan used file sharing networks to access and transmit the images, videos and stories as well as chat with other paedophiles.

In January last year, Coghlan, using the online name Tasbaby, shared child exploitation images with an undercover Australian Federal Police officer. 

Subsequently, a police search located two computers in his then Longford home containing more than 900 child porn images, 126 videos and 1600 pages of text relating to child exploitation.

Coghlan also sent about 3300 images of children in underwear and nappies that weren't pornographic but underscored his ``long-held interest in children'', Commonwealth prosecutor Elizabeth Curtis said yesterday. 

Computer chat logs revealed conversations Coghlan had with internet user diapers-of-fun where he complained ``it ain't easy being a ped''.

``[It's] just seen as a crime and not from the child's point of view,'' he said.

Ms Curtis said the number of victims could not be quantified but stressed Coghlan's offending stretched 5 1/2 years. 

She said the most serious aspect was Coghlan's online encouragement of other paedophiles, including a man who had access to a two-year-old. 

Defence counsel Alan Hensley said Coghlan's dysfunctional childhood resulted in his paedophilia, urophilia, and nappy, infantilism and transvestic fetishes.

He said Coghlan liked to wear nappies and be treated as a female infant.  

As a child, his mother made him wear female clothing after she had a miscarriage. 

Mr Hensley said Coghlan's mother and younger brother referred to him as ``little sister''. 

Coghlan's first ``consensual'' sex occurred with a 10-year-old girl when he was 12. 

In a report tendered in the Supreme Court in Launceston, forensic psychiatrist Georgina O'Donnell said this incident established his attraction to pre-teen girls.

Mr Hensley said Coghlan had been ashamed of his sexual tendencies all his life and had sought help from medical practitioners. 

When the police finally knocked on his door, Coghlan felt a ``tremendous sense of relief that he'd been caught''.

Justice Robert Pearce remanded Coghlan in custody for sentencing on December 10.