It was an "on again, off again" relationship between Joshua Levi Rowlands and his partner but when she finally ended it he sent her numerous text messages threatening to kill or seriously harm her.
Before Judge Tony Walsh the 19-year-old pleaded guilty in Masterton District Court to threatening to kill or cause grievous bodily harm and was sentenced to nine months' supervision.
Police prosecutor Sergeant Garry Wilson said on July 19 Rowlands' partner sent him a text message ending the relationship.
During the next three days the Martinborough vineyard worker sent a number of text messages asking her not to end the relationship.
Then, during an 11-hour period on July 23, Rowlands sent 15 "highly threatening" text messages to the woman, threatening to kill her or do grievous bodily harm to her, Mr Wilson said.