The New Zealand Veterinary Association is warning trick-or-treaters to spare a thought for their pets this Saturday night.
Halloween is a bad time of year for black cats, with their long-standing connections with witches, hubble-bubble and evil.
Veterinarian Pieter Verhoek warned petowners to keep black cats away from children who might play pranks.
Reports of deliberate cruelty to black cats rise especially in the weeks around Halloween in Britain, the RSPCA animal charity said on Wednesday.
Verhoek said dogs should be restrained and protected from getting over-excited by a series of visitors to the front door which could result in someone getting bitten by accident.
Treats and trick-or-treating should also exclude pets, Verhoek advised.
"Lollies and chocolate are not good for cats and dogs, and in some instances can be toxic. Especially with chocolate, which can result in animals getting seriously sick or even dying. We do suggest that such treats are kept out of the reach of our pets.
"If the kids want to dress your dog or cat in a costume - please be sensible - ensure that the animals are comfortable and not restrained by unaccustomed clothing," he said.