WELLINGTON (AFP) - A disgraced Malaysian diplomat who "terrorised" and indecently assaulted a woman in New Zealand was sentenced on Thursday (Feb 4) to nine months of home detention.

Mohammed Rizalman Ismail, who was a military attache at Malaysia's Wellington embassy at the time of the attack, admitted to indecent assault last November after denying initial charges of attempted rape and burglary.

Rizalman had followed Wellington woman Tania Billingsley to her home in May 2014, waited about 30 minutes outside and then entered the house and walked into her bedroom naked from the waist down.

"You terrorised Ms Billingsley... She was a young woman, alone in her room, who was entitled to feel safe and secure in her bedroom," Judge David Collins told Rizalman during sentencing.

"No woman should have to endure the terrifying circumstances experienced by Ms Billingsley when you breached the sanctity of her bedroom."

The judge said Rizalman's actions were "premeditated". Ms Billingsley was not touched in a sexual way and Rizalman had hoped she would agree to sex.

"You mistook a smile for a sexual advance, you deliberately followed her and waited outside her home for a long period of time," the judge said.

Rizalman is to serve nine months confined to a house, but not the Malaysian High Commission, and will be deported at the completion of his sentence.

His lawyer Donald Stevens had cited extenuating circumstances including mental illness.