An Auckland man says he is disgusted Auckland Council put down his dog, despite it being microchipped and registered.
Nick Brady moved house to care for his sick father but says he notified authorities of the change.
Mr Brady and his dog Patu had a special bond, and he says the hound was his "second son".
"I was lucky to get him, to give him a life, and he gave me a life."
Mr Brady says he updated his contact details the day after Patu went missing, and was assured all shelters in the area would be notified and if Patu was found he would be contacted.
But his contact details hadn't been updated and the council couldn't reach him.
Auckland Council says it was a mistake.
"That was a mistake that was made in not matching the details he provided when he called, to the details already existing."
Mr Brady finally found a letter at his previous address warning that Patu would be put down after seven days. He was three days too late.
"It's absolutely disgusting," he says. "I've had no follow-up call about his body, or ashes, or an apology yet."
"This has really been an eye opener for staff about what can go wrong," a Council spokesperson says. "They're really devastated by this mistake, and we apologise absolutely."
But Mr Brady says nothing will bring back his best friend.