A man had been drinking when he punched his partner in the head.
23-year-old Richard Oriwa Matthews pulled his partner backwards with his forearm around her neck and hit her on top of the head.
The victim told Matthews she was going to call the police.
"Ring them. I've done wrong. I know what I've done," Matthews said to her.
Matthews pleaded guilty to assault on a person in a family relationship and appeared in Whanganui District Court for sentencing.
Judge Philip Crayton said Matthews, who had no previous convictions, now has one for family violence offending.
"You need to be very clear in your understanding that with one conviction for family violence, the court takes a constructive approach which is intended to try and ensure that you gain some skills and insight so that it doesn't happen again.
"The second time something like this occurs, the court tends to very quickly go to punishment and protection. That tends to involve imprisonment very quickly."
Judge Crayton sentenced Matthews to 12 months' supervision.
"I hope that with that approach there is going to be no doubt that you will not appear again."