The man did not seek to appeal his nine-month home detention sentence but challenged the order to be placed on the Register.
The appeal raised two primary issues - whether the Registration Act applied to him, given he had offended before the law came into effect, and whether, if it did apply, the Judge should have ordered his name be applied to the Register, given that his level of offending did not require imprisonment.
Judges Winkelmann, O'Reagan and France found that the law was not clear enough to override the rules in the Sentencing Act 2002, which states an offender is entitled to the lesser penalty if the law is changed after committing the offence.
Judges William Young and Glazebrook disagreed and held that the Registration Act applied to all offenders convicted of a qualifying offence and sentenced to a non-custodial sentence after the law came into force.
By majority, the Court found the law did not apply to those who committed a qualifying offence prior it to coming into force and the registration order was quashed.
The law does, however, automatically and retrospectively apply to child sex offenders serving a prison sentence.
Despite quashing the order, the members of the Court went on to discuss whether the order should have been made, if it had been allowed to apply retrospectively.
Three of the judges believed the court must be satisfied the offender posed a real or genuine risk to children and that the risk was of sufficient gravity to justify making the order with the consequent impact on the right of the offender.
Chief Justice Winklemann and O'Reagan said while the appellant posed a real risk to children, it was not high enough to justify being on the Register.
Justice Glazebrook believed the order was proportionate and would have dismissed the appeal, as would have Judge William Young.
Justice France did not consider it necessary to express a view, given her view that the Act did not apply to the offender.