Veterinary scientists are calling for manufacturers to adapt to the growing demand for vegan pet food.
An international study has found about 1.5 percent of cat and dog owners feed their pets solely plant-based food, and at least 15 percent more are interested in vegan diets for their pets.
Two of the researchers involved in the study are from Massey University.
Senior veterinary science lecturer at Massey University, Nick Cave, said some pet owners felt uncomfortable about the intensive farming of animals used for pet food.
People also wanted an option that was less damaging to the environment, he said.
There was no reason pets could not live happy, healthy lives on a completely plant-based diet, but more research was needed, Dr Cave said.
"You can make nutritious diets that are healthy, that lead to flourishing, healthy long lives for cats and dogs," he said.