Three hunting dogs that were "accidentally let loose" mauled a pet greyhound on a beach north of Auckland on Tuesday evening, leaving it bleeding and unresponsive.

A police spokeswoman initially said that the canine victim had died from its injuries at Orewa Beach and that it was attacked by pit bulls rather than hunting dogs.

She later said that new information indicated the greyhound would likely survive.

"The greyhound went to the vet and while it's not in a good way, the vet said it would live," the spokeswoman said.

She said that its attackers were "three crossbred hunting dogs" - not pit bulls, as police originally stated - and had been in cages on the back of a ute parked near Orewa Beach.

Police were called to Orewa Beach at 6.35pm to deal with the aftermath of the attack.

"They were accidentally let loose and ran down the beach after someone's pet greyhound and attacked it," she said.

When it was still believed that the dog had been killed, one woman took to Facebook immediately after the incident to warn beach-goers about taking their dogs to the area.

Andrea Jane wrote a now-deleted post saying that "a couple of pitties just mauled another dog to death ... Don't know if the dogs are caught but be careful if your heading there to walk your dog!"

A frenzied debate on the dangers of pit bulls ensued on the Hibiscus Coast community Facebook page, although the dogs in question were not pit bulls.

Many posters called for the attacking dogs to be euthanised and for pit bulls in general to be banned, while others claimed aggressive behaviour came down to a pet's upbringing.

Jane Kenny-Mccabe posted that her shiatsu was "10 x the s*** stirring a****** that my previous pit bull ever was."

"In fact he was the best family dog I ever had so no, don't agree with banning them," she wrote.

The aggressors had been seized by animal control and their owner was cooperating with police.

It has not been confirmed whether or not the three assailant dogs would be put down.