Hoons are smashing barriers, driving cars on to sports fields and leaving a trail of destruction through parks and reserves in South Auckland.
Auckland Council is urging residents and sports clubs to be "extra vigilant" after vandals hit 15 times and damaged eight parks over the past two weeks.
"Most of the damage occurs at night and out of sight, making it difficult to identify the offenders," said Malcolm Page, the council's local and sports parks (south) manager.