Auckland Council had more than 800 complaints of dog attacks on people last year and is looking at tougher penalties for their owners, including disqualification and prosecution.
A quarter of the dogs in attacks were unregistered, said council planning, policies and bylaws manager Andrew Pickering.
He said the council had a number of ways it could address the problem in a review of the seven councils' dog policies and bylaws inherited by the Super City. These included the dog being seized or destroyed.
The owner could also be classified as probationary or disqualified, fined or prosecuted. Where a person was seriously injured the owner could even face prison.
Mr Pickering said dog control officers estimated that 11,000 dogs, or 10 per cent of the city's dog population, were unregistered.
"Reducing the number of unregistered dogs is a priority. However, it is going to be an ongoing job due to changes of address, owners both within and in and out of Auckland, and dog births and deaths."
Accident Compensation Corporation national figures show 9500 claims each year for injuries caused by dogs, including bites and sprains and strains, which may have been caused by falling over a dog.
Reducing the claims, as well as complaints, are aims of the review, said Mr Pickering.
He said the Dog Control Act was adequate for dealing with dogs known to be aggressive by their behaviour or type. For example, the American pitbull terrier could be classed as a dangerous or menacing dog and owners must meet further obligations such as putting a muzzle on the dog before taking it into a public place.
"We are exploring ways to prevent problems before they arise."
Also up for discussion was a requirement for all Auckland residents to hold a licence to have more than one dog on a property.
Mr Pickering said it had not been decided whether a licence would apply to only urban areas.
The review was looking at an exemption for working dogs.