Rotorua dogs are being stolen either to be used as bait in dog fighting rings or to sell for a quick buck, according to the Rotorua SPCA.
Manager Eve Johnson said they had reports of dogs being taken during the day while owners were at work.
Staff had heard of cases where properties are scouted and marked then the dog was snatched. She said while it might seem like an urban myth, the dog snatching was believed to be going on locally. There had also been reports of people going around neighbourhoods at night "whistling" to see whether dogs responded before going back to take them when nobody was home.
Mrs Johnson said there were four reported thefts last week, and probably more that weren't reported.
She said in one case the owner offered a reward and the dog miraculously reappeared.
She said it was possible a dog fighting fraternity had moved into town.
Mrs Johnson said they wanted to get people to be more vigilant about their dogs' safety and what was going on in their community.
"We are asking people to be vigilant about where their dogs are, making sure their gates are secure and if they see someone unusual or an unusual marking to get in touch."
She said it was also a reminder for people to make sure they reported their dogs if they went missing as most were microchipped.
"We just want to try and stop it. If we catch people in the act we can prosecute them."
Mrs Johnson said if people were stealing the dogs to be used as bait it was "very concerning".
"It's a part of your family. It's like stealing a child."
Police acting area crime prevention manager for Rotorua Senior Sergeant Nicky Riordan said the police hadn't noticed any particular spate or pattern of offences.
"From time to time we do have dogs reported stolen. The breeds vary so it's difficult to draw conclusion as to why they are being stolen."
She said police encouraged owners to report any dog thefts.