More than 1200 dangerous dogs have been registered under the Auckland Council's offer to do it for free.
Since April, the council has waived the registration fee for dogs classed as menacing breeds, and for $25 offered to neuter and microchip them and give them a muzzle.
That amnesty ended today with animal control officers set to launch a city-wide crackdown on dangerous breeds.
It covered the Brazilian Fila, Dogo Argentino, Japanese Tosa and Perro de Presa Canario - along with Pit Bull Terrier-type dogs.
The Auckland Council said 1228 dogs were registered and microchipped during the three month amnesty.
The council's manager of animal management Geoff Keber said the number of sign-ups had far exceeded expectations.
"We thought we might get one or two hundred dogs signed up but we've got twelve hundred now and that's really good and that's really great buy-in from the owners of Auckland."
He said with a large migrant population coming from countries without dog registration, it was a lesson for council around how to engage with parts of society unaware of the rules.
The amnesty was introduced after a spate of four separate dog attacks on children in four weeks over March and April.
"We've noticed since the amnesty's been going that there has been a drop off in attacks reported to us. Ideally obviously the idea of the amnesty will be that we will drop off these bites even more and hopefully reduce the risk and the harm that some of these dogs cause to Aucklanders."
Auckland has around 112,000 registered dogs.
Mr Keber estimated there were an additional 20 to 25 percent of dogs that the council didn't know about, some of which would be menacing breeds.
The council will today crack down on those remaining unregistered dogs which would be taken to shelters. If issues weren't resolved with their owners, the dogs would be put down.
"We're going to have a team of ten people that are going to be out going door-to-door and picking up the dogs that are menacing, and the people aren't complying with the classifications or the dogs that are unregistered."
Mr Keber said they would be starting at problem areas, such as South Auckland, and would take several months.
