A pet dog died after ingesting an entire packet of "highly toxic" disposable heat packs. Following the tragic death, the dog’s owner has issued a warning against hand and foot warmers.

Sharon Patterson, from Sydney, said she bought the golden retriever from a breeding business late last year. The pooch found a packet of Hot Hands Hand Warmers at home last month and ingested it. Patterson saw the canine vomiting and rushed it to the vet.

“He received urgent vet treatment, staying at the emergency vet overnight. He seemed to improve, the vets thought maybe the iron hadn't been as potent as the hand warmer had been activated, and it seemed he had been able to vomit up all the contents,” she said, adding that the dog was shifted to the intensive care unit after his health got worse the following day.

“Sadly, he had sustained organ damage, he deteriorated through the night and died. This has been a huge warning to us, I would not want to hear of this happening to anyone else,” she said.

Speaking to Yahoo News Australia on Thursday, Patterson warned people about how dangerous the heat packs were for animals.

 “There should be a warning on the hand warmers themselves: ‘Toxic, not to be consumed.’ Silica sachets found in vitamins have this, but there is absolutely nothing, not even a name, on the hand warmers,” she said.

Asking pet owners to remove the products from their home, she said, “Please, if you use these types of air activated hand warmers make sure they are kept where your dog (or cat) can't reach them. Also, when you dispose of them make sure it's somewhere animals can't get to. Personally, I don't think I'll have these in our house at all.”