Petitioner AnnMaree Mills claims the injection is an affordable option at around $10 per dose but shooting is recognised as a method of euthanasia in the code of welfare for dogs.
PNCC works closely with the SPCA, PAWS Animal Shelter and the public to find homes for unwanted dogs. Carcasses are offered to the owners, cremated or given to Massey University for study purposes.
Mr Jameson said pitbull breeds, who were classed as menacing, were not rehomed. Statistics show this breed is the most commonly impounded dog in New Zealand.
Research states their "misunderstood" nature leaves them susceptible to owners who use them for breeding or fighting and have little knowledge of how to control their dog.
The American Temperament Test Society also states pitbulls rank highly in temperament tests with 84-85 per cent pass rates.