Another parent said she bought a Scooby Snack multi-pack on Tuesday during her weekly shop believing it was children's food.
"I was absolutely mortified when I gave them to my daughter. She took one bite and said, 'this is rubbish'.
"I looked at the packet closely and gasped, 'Oh no, I am so sorry. I just fed you dog food'."
She said many people had been caught out by the placement of the pet-food multi-pack next to similar-style chip multipacks.
A multi-pack of shaped biscuit snacks called Scooby-Doo! and featuring the same cartoon character is also available in supermarkets.
One concerned mother said she had contacted Pak'nSave about the mix-up. She said they appeared more amused than concerned people would buy them to eat.
However she said people were often in a rush and duped by similar packaging. There was also nothing at the store to indicate it was pet food.
Foodstuffs NZ head of external relations Antoinette Laird said that, on reflection, they could see how the cartoon characters on the packaging caused confusion.
"The bin of 'Scooby Snacks' was clearly labelled as 'Pet Treats' but unfortunately it appears some customers mistook them for human food.
"The store relocated the product to the pet food aisle, and has since decided to withdraw the product from sale and return it to the supplier."
Laird said the product packaging warned the product was a "pet food product only, human friendly but not recommended".
"We apologise for any distress this has caused to anyone who bought the product by mistake and will happily offer a refund to any customer in this position."