Organisers of a national mountainbiking race are offering a reward to catch vandals who sabotaged the event on Sunday.
They pulled arrows off trees and restapled them pointing in the wrong direction in Whakarewarewa Forest, near Rotorua.
That led to a competitor riding 75km, instead of the 45km race he entered, nearly sparking a search and rescue operation.
Organisers said he was so exhausted after his seven-hour ride that he left the course and went to get food, neglecting to hand in his transponder.
Marcus Diprose, event director of the Highlander Mountainbike Marathon Championships, said the sabotage happened after the safety motorbike and lead competitors had passed through the course.