The woman was asleep and woke to find O'Carroll indecently assaulting her.
When the victim returned to New Zealand, she made a complaint with police and, with the leave of the Attorney-General of New Zealand and Solicitor-General of the Cook Islands, O'Carroll was charged.
He first appeared in the Auckland District Court but his case was transferred to the High Court.
O'Carroll pleaded guilty to a charge of indecent assault in May last year after he was given a sentence indication of three years in prison with a discount for guilty plea and the possibility of further reduction based on other factors.
The indication was given in line with Cook Island law.
There is no home detention there - so there was no option for the sentence to be converted to something community-based.
The basis of the appeal was whether or not the High Court in New Zealand had jurisdiction to commute any short-term sentence of imprisonment to one of home detention.
The appeal found the High Court did have jurisdiction to impose a sentence of home detention when sentencing O'Carroll.
O'Carroll will reside at a residential address and will not move from that address without the prior permission of his probation officer, Justice Williams said in the report.
"If found suitable, Mr O'Carroll is to attend Te Ihu Waka as may be directed by the probation officer.
"Mr O'Carroll is to attend alcohol and drug counselling as may be directed by the probation officer."