But Supreme Court Justice Peter Evans said Kevin Charles Rose, 46, caused harm by the sheer number of images and stories he viewed.

``Largely because of the very substantial number of children who must have been exploited in the process of the creation of the many images accessed by the defendant, I consider that an immediately effective sentence of imprisonment is necessary,'' Justice Evans said.

Rose was jailed for six months yesterday after pleading guilty in the Supreme Court in Launceston on Thursday to accessing and possessing child pornography.

The court heard Rose viewed child pornography for an hour a day in the three years before police searched his house on December 20, 2011.

He told police that he downloaded and saved about 4 per cent of what he viewed, or 15 images, two or three times a week during that period.

Commonwealth prosecutor Elizabeth Curtis said that based on Rose's own admissions it could be estimated that he had viewed tens of thousands of images.

``I should say at the outset that I reject the defendant's claim to police that he obtained no sexual gratification from viewing the pornographic material,'' Justice Evans said yesterday.

Police found 12 images and 16 text documents depicting child exploitation in the search of Rose's home.

Justice Evans said the text documents, which amounted to 116 pages, were ``very depraved''.

``I recognise however that the generation of the stories, unlike the images, did not involve exploiting children,'' he said.

Rose was jailed for six months.

His name will be placed on the sex offenders register for five years when he is released from custody.