A strange form of vandalism has taken place multiple times on the Kapiti College cricket pitch, north of Wellington.
Striking in the middle of the night, sand and shells likely taken from the beach have been dumped on the wicket area.
"It's very strange, we have no idea why," Kapiti College principal Tony Kane said.
"Time and effort goes into making the pitch a safe surface for our students to play on so for someone to try to sabotage it is disappointing."
The vandalism is believed to be a deliberate act of vandalism as the sand has been dumped only on the wicket area.