The DSPCA received over thirty calls about horses tied up with no access to shade or water on one day alone last week.
The charity says it's horrified to find people are still leaving pets unattended during the continuing weather.
It has received numerous reports about dogs being left in parked cars for long periods of time.
This week, one dog was reported to have been left in a car for over an hour.
In another case, inspectors had to take a dog out of a car as the owner was not present.
In a statement, the DSPCA said: "Animal owners need to realise the dangers that the hot weather can cause to their pets and other animals."
The charity added it had been "inundated with calls" about horses tied up across the city during the high temperatures.
Warm weather has continued across the country for almost two weeks now, with Met Éireann forecasting that the "rather exceptional spell" of weather will continue well into next week.