When Pat Newman watched security footage of children and youths vandalising artwork his pupils had worked so hard on - he was "very very angry".
Now the Hora Hora Primary School principal has a message for the parents of those involved.
"I think it would be far wiser for the parents of those people involved to come along to school with them rather than me getting someone else in blue uniform knocking on their doors," he said.
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Newman had gone into the Whangārei school last week to prepare for the start of term one. When he arrived he found little houses, a plane and other artwork made by his pupils had been damaged.
He went back to his office to check the security footage and found the art was destroyed in two separate acts of vandalism on January 6 and 12.
"It's mindless. It's not even as if it's the school's work, it's the kids' work. And the one that really annoys me is particularly the older ones, who look like they're teenagers, spent the afternoon using our facilities playing basketball and all of that and as a thank you they decided to wreck the place," he said.
Footage from January 6 shows two youths shooting hoops on the court before making their way to the back of the school. One of them then climbs on top of a storage container - where a plane made out of recycled materials is sitting - and pushes the plane off, destroying it.
Another video from January 12 shows two children in the same area pushing little houses down the cliff and throwing rocks at them before flipping over a dinosaur.
Newman said the artwork was made by pupils in an art and construction programme run by teacher John Moffat.
The houses were made by children wanting to make a little village, the planes were there to show children what can be made using scrap material, and the dinosaur was made to protect the place.
"The fact they've been there for over a year, the fact that kids use to go play with them and on them and around them and all of that, the fact that these darling little children smashed it all up - I was very very angry."
Newman has posted the videos on the school Facebook page and already has some names.
He said the school's 25 surveillance cameras were installed for security and have been "extremely useful".
• If you know who is responsible for the damage contact Hora Hora Primary School.