Primary students and their families came together on Monday to help clean up the mess at Wanganui East School left by taggers and vandals.
Parents, staff, and children were dismayed at the weekend to discover tagging around the school, as well as smashed windows and playground railing, principal Eleanore Barry said.
"A group of teenagers -- I'm not sure who they are or how old they are -- painted the school walls and smashed a few windows," Mrs Barry said.
"They damaged our playground as well... on the senior playground they have totally demolished all the railings and all the safety barriers. That's going to be a significant cost to the school to fix the playground."
Mrs Barry said about nine families gathered on Monday to clean up the mess, which included words painted across the playground and buildings, such as "Prone", "Priest", and "FTP" (f*** the police).
"Our parents have been amazing," she said.
"Some of the parents said that the children were really upset that their school had been painted on. They're upset because it's their school and they had pride in their school.
"It's more an emotional attachment to the school for the children. To see their school defaced."
She could not say yet how much the clean-up and repairs would cost.
"It's just really disappointing, because we were changing the colour of the school and working really hard to brighten it up."
Parent and PTA head Tracy Hutchins, said it was "heartbreaking" to see so much tagging.
She had shared photos of the graffiti on Facebook.
"There's a picture of a mural on there that I put up; the kids worked to do that. They've painted over that, and it's so hard to get off. They've actually taken it down."
Her 9-year-old daughter, who attends the school, "just couldn't believe how they had done something so mean to the school", Ms Hutchins said.
Senior Sergeant Shayne Wainhouse said nobody had yet been caught for the crime.