The SPCA is urging owners not to leave their dogs inside hot cars, after responding to several incidents in Wellington on Wednesday.
Inspectors responded to six incidents of dogs in distress, including two cases where dogs had to be broken out of the vehicle.
One dog found scrambling for shade was the worst example they had seen this year, SPCA chief executive Andrea Midgen said.
"It was trying to crawl under the seat, in the footwell sort of area to get a bit of shade and it was drooling and sadly, urinated on itself in distress and so we needed to smash into the car and take it back to the hospital to get it checked out."
When the dog owners returned to find their car window had been smashed, they abused the SPCA inspectors.
"We're sorry about that but we needed to get the dog out and they are doing what's best for those animals - unfortunate about the car, but don't do it."
In 21 degree heat as it was in Wellington on Wednesday, within 10 minutes the temperature inside a car can reach 31 degrees and in half an hour, it can reach 40 degrees. One of the dogs was left in a car for 40 minutes.
Ms Midgen said that could be deadly, with a number of dogs dying from heatstroke last year.
"If the purpose of your trip is not for your dog, we're suggesting you leave them at home."
She said people can be fined up to $300 for leaving their dog in a hot car.