Karaka berries are an important food source for kererū but are toxic to many other animals, especially dogs. Photo: Supplied
Dog owners are being urged to keep their pets well away from the berries of a native tree currently fruiting around New Zealand.
The large orange berries of the karaka tree are feasted on by kererū, or native pigeons, but they are toxic to dogs.
New Zealand Veterinary Association president Kate Hill said karaka toxicity had been recorded in humans, sheep, cattle, chickens and other species - but dogs were especially sensitive to karakin, an alkaloid present in the berries.
Dogs that ate the fruit when it dropped to the ground could suffer respiratory failure, impaired neurological function, and, in extreme cases, even death.
She said the trees fruited between January and April, and some trees around the country were "absolutely laden" with berries.
Hill said the signs of karaka berry poisoning in dogs could take up to 48 hours to appear.
Symptoms included vomiting, diarrhoea, reduced appetite, abdominal pain, paralysis of the back legs, loss of balance, convulsions, and reduced breathing.
Karaka trees are laden with berries at this time of year Photo: Supplied
She said early treatment was best so anyone who thought their pet may have eaten the berries should call a vet straight away.
Owners should also keep their dogs on a lead around karaka trees.
Even if a dog had eaten berries and showed no signs of toxicity within one to four hours, it should be taken to a vet clinic and made to vomit, Hill said.
Karaka berries were historically a valued food source for Māori but they were subjected to a long preparation process to remove the toxin and make them ready to eat.