Magistrate Brian van Zuylen appeared on audio visual link in Port Macquarie Local Court to sentence Nicholas Francis O'Callaghan, who was convicted of indecently assaulting a child and possessing child abuse material on July 25.

O'Callaghan was represented by Michael Dampney on Monday, who said the purpose of his client's possession of 4025 files of inappropriate material was important.

"He was collecting this material to remind of an erotic experience he had around the age of 15," Mr Dampney said.

Prosecutor Geoff Kidd, acting for the NSW Director of Public Prosecutions, emphasised the "considerable quantity" of material. 

"For someone to even describe the images as cute doesn't carry any weight," Mr Kidd said. "They are sexually explicit in the extreme.

"Given the abhorrence the community has for offences of this nature, the only appropriate sentence is imprisonment."

O'Callaghan received an 18-month sentence for the indecent assault, with Mr van Zuylen taking into account the defendant's "special circumstances".

The assault sentence has a non-parole period of 12 months, meaning O'Callaghan will be eligible for release on October 12, 2015.

He will concurrently serve a nine-month sentence on the possession of child abuse material charge, which has a non-parole period of four months. 

After O'Callaghan was led from the court, Mr Dampney appealed the sentence.

He said O'Callaghan had no criminal record prior to the offences, had not gone near his victim in more than a year, strictly adhered to bail conditions and would willingly surrender his passport.

Mr Dampney also said his client's parents could lodge $10,000 as surety.

But the magistrate said there was still a risk of O'Callaghan committing a serious offence.

"In the court's view, the seriousness of the charges mean there are no conditions that could mitigate the risk."

O'Callaghan is appealing to the District Court over the severity of the sentence for possessing child abuse material, as well as his indecent assault conviction.