"If a dog attacks someone, the owner should automatically be charged with assault as such a dog is essentially a loaded weapon ...
"Dogs kill people in New Zealand. If you own dogs and they kill somebody you should certainly be charged with manslaughter."
Professor Stafford, who owns three dogs, would also like to see dog control laws simplified, so canines are classified as either dangerous or non-dangerous. Owners of dangerous animals should be encouraged to have them euthanised, he says.
Otago University law professor Mark Henaghan said assault laws probably wouldn't work for dog owners, because some intent to cause wrong-doing was needed.
But laws governing being in charge of a dangerous thing or assault with a weapon might apply in some cases, as could manslaughter.
Professor Henaghan thought it might make more sense to legislate for an owner's carelessness or recklessness. "I think you've got to make the offence fit the circumstances rather than extend the law of assault, because I think that's tricky to do."
SPCA's Auckland chief executive, Andrea Midgen, said she couldn't support a call for all dangerous dogs to be euthanised.
"Some other methods ... could be used, for instance all of those dogs should be desexed. Also those dogs could go through temperament testing to assess their suitability to be out in the community."
Dogs with unsuitable temperaments were not rehomed by the SPCA and euthanasia was one way of dealing with them, she said.
Tuesday's Christchurch attack was stopped by a neighbour, who said the dog was on heat and went "ballistic".
Cory Whyte was watching TV at home when he heard a woman screaming next door.
He rushed outside and saw a staffordshire-cross dog latched on to his neighbour - a 23-year-old woman about 30 weeks pregnant. It was biting her feet, legs, and forearm.
A quick-thinking Mr Whyte, who used to breed miniature staffordshires, started kicking the fence. That distracted the dog long enough for the woman to get to safety inside.
A male dog had been brought around to mate with the bitch before the attack, he believed.
The two dogs were seized by Christchurch City Council's animal control unit, which is investigating.
The woman suffered moderate injuries and was taken to hospital for treatment, St John said.
And on Saturday, Darnell Minarapa-Brown, 7, was attacked by his uncle's dog in Takanini, leaving him needing more than 100 facial stitches. The dog was euthanised.
Two studies presented by Kiwi medical professionals last year show hospital admissions for people with dog-bite injuries average two a day.
A study published in August found 99,000 dog bites had been recorded nationally in the decade to 2014, with more than 5800 requiring hospital treatment.
Incident rates increased from 10.5 attacks per 100,000 people to 14.3 over the 10-year period.
More than 2500 charges were made under the Dog Control Act in the past five financial years. A little more than 350 dog destruction orders were granted in that time.
Other recent dog attacks
• Dec 1 2015: A woman was attacked by three Irish wolfhounds while delivering mail in Dunedin. The attack was so vicious the woman recalled thinking she was going to die.
• March 4: A woman was attacked by two dogs on a South Auckland property. She was taken to hospital in a moderate condition.
• March 10: Blockhouse Bay Intermediate School went into lockdown after a teacher was attacked by two vicious dogs on school grounds.
• March 28: A 10-year-old Waiuku boy had his face badly bitten by his best friend's family dog. The dog was immediately put down.
April 5: The grandfather of a 6-year-old boy mauled by a dog pleaded guilty to a charge of being the owner of a dog that caused injury. The Tauranga man's dog attacked in October last year while his grandson was trying to feed it.
April 6: Christchurch police shot and killed a dog during a property search after it started attacking a police dog.
New app to help you be safe around dogs
A Dog's Story, a world-first interactive app to help keep children safe around dogs, has been launched in Auckland this week.
Animal management officers from Auckland Council will visit schools with training dogs, teaching children how to use the app and getting them to practise their newfound skills with the dogs.
Parents are also being encouraged to download the app and play the game at home with their children. It is available as a free download from the App Store and Google Play.
Go to ourauckland.aucklandcouncil.govt.nz for more information
