A billboard referring to an islander couple who barbecued their pet dog and ate it has earned Hell Pizza yet more notoriety.

The controversial Kiwi fast food chain - subject to many complaints about its outrageous advertising gimmicks - has been censured yet again by the nation's advertising watchdog.

Earlier this year, police saw the dog being cooked on the backyard barbecue of a Tongan couple, who said they decided to eat it because it was a nuisance. The couple said dog was commonly eaten in Tonga.

No charges were laid because it's not an offence to eat dog in New Zealand and the dog had been killed humanely, said investigators.

Fast forward to August, when two billboards appeared in Auckland promoting Hell Pizza's brownie cakes.

The billboards carried an image of a man about to bite a piece of the cake. Large accompanying text read: "At least our brownie won't eat your pet dog".

Underneath were the words: "Pitch gluten free brownies coming soon", and the Hell Pizza logo.

Angry complainants to the Advertising Standards Complaints Board charged that the billboards were racist, offensive and socially irresponsible.

Defending its actions, Hell Pizza claimed the ads were funny and lighthearted.

However, the Complaints Board didn't see the funny side and upheld the complaints.

Source: Advertising Standards Authority