Both Aaron James Holliday and the office of the Director of Public Prosecutions have appealed against Justice Richard Refshauge's decision to jail the notorious predator for 16 years, with a non-parole period of seven years.

The 26-year-old was locked up for ''sinister'' child abuse offences, including creating so-called training documents that purportedly taught the boys how to help police catch paedophiles in a fictitious ''operation paedobait''.

Holliday abused two of the boys while on bail for showing pornography to a third, despite court orders forbidding him from being with children under the age of 14.

He also pleaded guilty to theft and possessing more than 11,000 images and more than 700 videos on his computer ranging from ''erotic'' images of children to hardcore child pornography and bestiality.

He has been placed on a sex offender register.

Holliday's barrister, James Lawton, argued sentences for the counts of theft and possession of child pornography were "manifestly excessive".

He said the full sentence of 16 years and six months imprisonment was "crushing" for a man of Holliday's age and previously clean record.

He sought to have the total sentence reduced by two years.

But Director of Public Prosecutions Jon White argued the sentence was "inadequate" and sought to have it extended.

Mr White said the discount applied to the jail term for Holiday's guilty plea was too high for such a late admission. Holliday was a risk of reoffending and had bleak chances of rehabilitation, he said.

Chief Justice Terence Higgins, Justice Hilary Penfold and Justice John Dowsett will hand down their decisions at a date to be set.

The Holliday case comes amid a continuing prosecutorial push against sexual offenders. It is the seventh challenge to ACT Supreme Court judges' sentences for sex offenders in the past two years.

Four of the other six appeals challenging the leniency of judges' sentences for sex crimes were upheld.

Last year, the court agreed that serial rapist Alfred Chatfield's five-year jail term for attacking a woman on Northbourne Avenue did not reflect his culpability and ''atrocious'' criminal record, and added another two years and three months.

And a man who used young children, including his one-year-old son, to produce pornography had his seven-year sentence increased to nine years and seven months.