More than 40 per cent of Auckland's menacing and dangerous dogs are not microchipped, two years after it became mandatory.
Only 6 per cent, or 1092, of the 19,012 dogs known to the Auckland City Council are not microchipped.
But 179 of the 418 Auckland City dogs classified
as menacing and dangerous are un-microchipped.
The rule was intended to reduce attacks on humans by dangerous dogs, Auckland SPCA chief executive Bob Kerridge said.
The results showed it had not worked.
"When microchipping was being sold to us, it was to be a weapon against dangerous dogs. Well it's not."
Dogs classified as menacing under the Dog Control Amendment Act 2004 are the Brazilian fila, dogo argentino, Japanese tosa, and American pit bull terrier.
Dogs are officially classified "dangerous" if they have attacked someone, or shown aggressive behaviour.
Working dogs do not need to be microchipped.
Mr Kerridge said marketing microchipping as a way of controlling dangerous dogs was a "political stunt" and a mistake.
"We went about it the wrong way, assuming it was for enforcement purposes, rather than recovery."
But Auckland City's animal contracts manager, Clare Connell, said the microchipping legislation had been successful, and she encouraged all dog owners to get their dogs registered - even if they didn't have to.
"It is good, because if it gets stolen or goes missing we can return it."
Mr Kerridge agreed microchipping was "a brilliant idea" as a tool to keep track of pets.
It meant a lost, stolen or escaped pet could be easily identified and its owner's name established so pet and owner could be re-united with a minimum of fuss or delay.
But the only way to really change the threat of dangerous dogs was to target their owners, he said.
"Excluding pit bulls, dogs aren't born dangerous, they're made dangerous. As long as you have irresponsible owners, you're going to have dangerous dogs.
"If their pack leader is an idiot that doesn't know how to look after them, you're going to have problems."
There was a "macho" aspect of dog ownership for some people, Mr Kerridge said.
The best way to control that was to license owners, not dogs.
