A national pet adopt-a-thon will run this weekend as part of the "Second Chance for Love" campaign.
It is hoped 1000 cats or dogs will find new homes.
"If you're ready to bring a new cat or dog into your life, why not adopt?" SPCA chief executive Robyn Kippenberger said.
The Otago SPCA was hoping all animals at its shelter would be adopted, senior inspector Steph Saunders said.
"It would be wonderful if we could be cleaned out."
Three kittens and 20 adult cats, as well as three puppies and five adult dogs, were in the shelter earlier this week.
However, Ms Saunders expected more animals to be dropped off before the weekend.
It was important for people to understand by adopting from a shelter a person could get "a quality pet and quality advice".
"Nearly all animals are re-trainable and have a lot of love to give."
Not all animals there had a history of abuse or were cross-bred.
Many pedigree animals were now ending up in their care, she said.
The campaign was about people finding pets to love, and pets loving people in return, SPCA sponsor Hill's Pet Nutrition commercial manager Greg Boyce-Bacon said.
"In some cases not only one life is saved. People discover that a pet can actually rescue them from feelings of loneliness, depression or anxiety."
Spot prizes and giveaways will be available at each of the 22 shelters involved, as well as information on how to care for new pets.
SPCA understood not every person who visited the shelter would be in a position to adopt and a register would also be set up for people who were interested in adopting a specific type of animal, Ms Saunders said.
People considering adopting a new pet can visit the Otago SPCA at 1 Torridon St, Opoho, Dunedin.
