"Notwithstanding his poor health, Chip was determined to be wholly or predominantly American Pit Bull Terrier," he said.
"Auckland Council has a long-standing policy, as did all of the legacy councils before it, not to adopt out dogs that are of this type. The Dog Control Act allows councils throughout New Zealand to adopt this policy and many of them do. We strongly believe that this policy is in the best interests of the community as a whole."
Chip was underweight and in poor health, when he was picked up by council staff, Mr Keber said.
"He had been abandoned by an irresponsible owner when he was at his most vulnerable. It was evident to staff and the vet that assessed him that he had not received what all puppies need for a good start in life.
"Chip received nothing but the best of care while he was in our shelter. He had been seen by a vet and his wellbeing was monitored regularly."
However, the decision was made to put him down.
Mr Keber also said staff had been targeted by online bullies, and hit out at those attacking the council.
"This case has been distressing for everyone involved - from the person who found Chip to Animal Management staff who have been subjected to a considerable amount of online abuse. The people behind those comments need to be reminded of why Chip was in our shelter in the first place and that's because someone abandoned a sick and vulnerable puppy in his time of need," he said.
"The reality is that Chip is one of thousands of abandoned dogs that find their way into our shelters each and every year because of irresponsible dog owners and until that type of behaviour stops, little will change.
"We're proud of the way we run our shelters and the work we do to reduce animal-related harm in our communities. We're also proud to say that 100 per cent of dogs that come into our shelters, and are able to be adopted out, find loving homes."
