Mr Furze said the dog got the man on the arm and dragged him to the ground where the dog then bit him on his neck and leg.
He managed to grab a hammer and hit the dog a couple of times. He got to his feet but was bitten again before fleeing inside the house.
"If that had been an attack on a child the outcome could have been much worse," Mr Furze said. "They realised it was a dangerous dog and they made the decision to have it put down. I praise them for that."
St John ambulance staff took the injured man to Whangarei Hospital where he had five stitches to bites on his chest, arms, throat and legs.
Police called for animal control to come to the house.
The owner agreed the dog was not well socialised, unregistered and feared another attack so handed it over to animal control officers.
Environment Northland manager Keith Thompson said more of the Shar Pei cross dogs were turning up at the pound every month.
He said people saw the toilet paper advertisement on television that featured a Shar Pei dog but got the wrong idea about the breed. The Shar Pei breed of dog is known for its distinctive features of deep wrinkles and a blue-black tongue. The breed comes from China and was bred and used for dog fighting.
Mr Thompson confirmed the dog was to be put down yesterday.
There were about 122 infringement notices issued to dog owners in Whangarei last year, including 10 for serious attacks - mostly on other animals - that resulted in bite marks and puncture wounds.
Environmental Northland figures show only one dog owner has been prosecuted in court.
