"Just through the information we saw and had inferred, it looked like the dog had overheated."
SPCA manager Bruce Wills said he had heard about the incident and was investigating.
"We're just in the process of trying to track down the owners of the car were, we don't have a lot of information at this point.
"We've heard that the dog has died as a result."
Wills said it was the first time a dog had died from overheating in Napier.
"It just shows how easily it can happen. We're not scaremongering here, it's a reality that dogs can die easily from sitting in hot cars."
With temperatures sitting between 27 and 29C for most of this week, Wills said it was a reminder for people to keep dogs at home on hot days or to be cautious if they had to take dogs with them in the car.
"It's important to take all precautions and to not leave them in the car for any extended period. Make sure windows are down, water is available and you're parked in the shade."
"If you don't do these things the consequences can be dire and it can be a horrible way for animals to die."
Wills had previously told Hawke's Bay Today that during the past few years inspectors have had to break into a cars to rescue dogs which had overheated.
"It's a real problem for us over summer, the SPCA get a lot of calls about dogs in cars and some of them are genuine concerns where they see dogs in distress and some of them aren't.
"It requires a lot of time for inspectors to go and investigate to see whether it is a welfare issue for us."