"You can sense the ones that are going to become good writers."
It is Mealamu's sixth year illustrating the book and he is looking forward to "getting stuck into it".
"It's pretty awesome when its finished. Feels pretty special to be part of it."
Gracie said the win had encouraged her to write more.
"Especially entering a competition like this, it really boosts my confidence," she said. "I was aiming to win after coming so close last year."
Entries came in from more than 150 schools ranging from Pukekohe to Cape Reinga.
Barfoot and Thompson managing director Peter Thompson said the competition had increased by a third since last year.
The compilation of stories will be available in November, costing about $15-$20 per book and all proceeds are donated to Starship children's hospital.