In May 2014 Rizalman followed Ms Billingsley home and after defecating outside her flat, entered through an unlocked door and walked into her bedroom.
He was naked from the waist down and in a subsequent struggle grabbed Ms Billingsley's shoulders.
On the morning he was to go on trial he pleaded guilty to indecent assault on the basis the assault was indecent because of his semi-nakedness.
Rizalman, an assistant to the high commission's defence attache, had originally returned to Malaysia under the cloak of diplomatic immunity, but returned to New Zealand in late 2014 to face prosecution after a political firestorm.
After his guilty plea, Rizalman disputed he had a sexual motive when following Ms Billingsley home, but Justice David Collins disagreed.
However, unusually for an indecent assault, it was accepted Rizalman did not intend to sexually violate Ms Billingsley or force himself on her in a sexual way.
"It needs to be kept in mind that there was no sexual assault and no sexual attack. Rather, as we know, there was an indecent assault, because the defendant took hold of the complainant's upper arms, which he said he did to try and calm her down, and he did that as she, or immediately after, she leaped from her bed yelling and screaming at him," Dr Stevens said at the sentencing.
Ms Billingsley, who waved her right to name suppression, was terrified by what happened, telling police: "It's just, probably, the most horrible moment of my life."
