Wayne Wilmot, 51, was placed under strict conditions when he left jail earlier in 2024, including requirements that he be subject to electronic monitoring and not access pornographic material.
But the violent sexual offender was locked up again 11 days later after breaching conditions of the court order.
Wilmot pleaded guilty on July 5 to breaching an interim supervision order after seeking to access online pornography, much of which was of an extreme nature.
Magistrate Jacqueline Milledge on Tuesday sentenced Wilmot to a further 18 months in jail during a hearing in Waverley Local Court.
Wayne Wilmot has spent less than two years out of custody since the age of 15. (Joel Carrett/AAP PHOTOS)
The 51-year-old's lawyer, Dev Bhutani, said his client had been in custody almost continuously since he was 15, which the magistrate said was where he belonged based on his criminal history.
Ms Milledge described Wilmot's violent sexual offending as "quite worrying, if not frightening".
The court heard the material Wilmot sought to access included underage women and hardcore material.
"This is very, very concerning," Ms Milledge said.
"He's got on to significant hardcore porn sites ... not only involving sexual activity, but gang sexual activity."
Wilmot was one of five homeless youths convicted over the 1988 abduction of Ms Balding, a case that stunned the nation due to the brutality involved and the age of the offenders.
The 20-year-old bank teller was repeatedly gang raped before being bound, gagged and held underwater in a dam until she drowned.
Wilmot, who was 15 at the time, was found not to have taken part in the murder, but was sentenced to eight years in prison over the abduction and rape.
Mr Bhutani conceded a jail term was the only available punishment for the latest breach, but called for a "short, sharp" sentence in the vicinity of six months.
Before the attack on Ms Balding, Wilmot committed three other violent sexual assaults on women in public places.
After being released on parole in 1996, Wilmot robbed one female victim and assaulted another.
In 2023, he was acquitted of two separate charges related to sexual offending while in custody and was placed under an interim detention order, which was extended the maximum number of times to keep him in jail.
Psychological assessments conducted on Wilmot in 2019 found he had an IQ of just 74 and was highly callous, manipulative and deceptive, consistent with psychopathy.
He has spent less than two years out of custody since the age of 15.
