There were two feral cats and seven sick kittens put down at the shelter last week, she said, and other animals are still being successfully rehomed or fostered.
Mrs Ball said she was gobsmacked after arriving at the shelter just before Christmas to find an exquisite 5-year-old oriental breed cat left in a carry cage at the door. The male cat, which was worth up to $600, was desexed and in top condition and had been quickly found a new home.
"We want people to take cats because they want a friend, they want cats in their lives. We do try to foster them but foster cats and kittens come back."
She said the shelter was also working alongside the Masterton Seed & Pet Shop in Dixon St to house and rehome the animals.
Shop owner Tracey Cooper said the business had 22 kittens for sale and another 20 had been booked and would be taken in the coming weeks.
She agreed with Mrs Ball that the dumping of cats and kittens had not been as bad for some time and unwanted animals had been in the past abandoned at the back door of the shop in pillow cases, recycling bins, boxes and bags.
"We've just taken in 16 kittens in a couple of days because they were going to get either drowned or knocked on the head. It does make me feel blackmailed but in the end it's about the animals."
Mrs Ball said the Wairarapa SPCA requests a donation from people surrendering unwanted animals.
"We will always try to make room and the donations, which are not demanded, allow us to continue caring for the welfare of the animals."
Cats cost $50 and kittens $100 from the shelter and the animals are rehomed after being checked by vets, vaccinated and treated for fleas and worms. Adult cats also are desexed and desexing vouchers accompany kittens.
Standard "moggy" kittens from Masterton Seed & Pet Shop cost $95 each and also have been checked by vets, vaccinated and treated for fleas and worms.