Clinical psychologist Steve Berry said Chisnall was likely to commit offences against female adults and female children.
"Any future offending by the respondent is likely to be in the form of stranger violent sexual acts, against both adult females and female children, and given his impassivity, sexual assaults against known females are also a possibility."
Mr Berry noted Chisnall has had an intense drive and desire to commit relevant sexual offences from an early age.
Chisnall's defence argued he had been found intellectually disabled and the finding prohibited the court from issuing a public protection order against him. The court found, however, there was sufficient evidence to justify an interim detention order.
On 29 March 2006, Chisnall was sentenced in the High Court at Wanganui to eight years' imprisonment on one count of sexual violation by rape.
On 31 July 2009, in the New Plymouth District Court, he was sentenced to a cumulative sentence of three years imprisonment on one further count of sexual violation by rape.
The Department of Corrections has applied for a Public Protection Order or an Extended Supervision Order to be placed on Chisnall which will be decided once he completes his sentence today.
The orders would see Chisnall kept under indefinite supervision at a secure facility.
