More than 40 children from Halfmoon Bay School - aged as young as five - smashed their target of 500 rats in a 100-day rat-catching competition from July to October.

The winning rat-culler was 11-year-old Bella McRitchie-King, who caught 64 by herself.

The competition extended to awards for children who caught the biggest rat, and the rat with the biggest teeth or weirdest tail.

A local merino wool clothing company was called in to judge the best rat coat.

Board of Trustees chairperson Emma Jenkinson said the children were particularly excited about the biggest rat, which was a impressive 45cm long.

"They were excited to see how many they were catching. They're all pretty keen to have kiwi in their backyards without the rats," she said.

Aiden Gear, a student at Halfmoon Bay School. Photo: Supplied

Predator Free Rakiura's Bridget Carter said rats are a major predator to wildlife on Stewart Island.

Predator Free Rakiura aims to rid the island of pests to protect its biodiversity, including a population of 20,000 kiwi.

Indi Jenkinson, a student at Halfmoon Bay School. Photo: Supplied

Carter said the children's efforts were inspiring.

"What an awesome project, and they really, really did deliver."

Stewart Island/Rakiura Community & Environment Trust donated the rat traps to the children, who received a range of prizes supported by conservation groups.

Anna Sargent , Reporter

Published by arrangement