The motoring body’s Renee Smith said there was no safe time for pets to be left unattended in cars.
“In a minute or two the temperature inside of a car can go from air-conditioned, to ambient,” Ms Smith said.
“It’s shocking how quickly it can deteriorate from there. In just seven minutes the temperature can reach 40 degrees Celsius.
“Medical experts say 40 degree temperatures can lead to serious injury and even death.
“In one of our tests, the peak cabin temperature was more than 75 degrees.”
Ms Smith said motorists shouldn’t be fooled into thinking their pets were safe, simply because the windows were slightly open.
“Having the windows down a little, hardly changes the cabin temperatures,” she said.
“Our testing shows regardless of whether the car is light or dark, the actual peak temperatures vary by only a few degrees.”