Founder Megan Denize said kitten littering was a "huge problem" in Northland and the reasons for that were two-fold, she said.
"A lot of vets recommend de-sexing at six months but we recommend that it be done earlier because cats can become pregnant at four to five months old.
"Another issue is affordability. A vet close to us is charging $167 to de-sex a cat which is a lot of money. Add on top of them vaccination and microchipping," she said.
Denize said one way kitten littering could be controlled in Northland was for vets, community groups, and animal rescue organisations to work together to bring the cost of de-sexing down.
She has 35 names on the waiting list since the free de-sexing offer was made.
The centre has begun a pre-adoption process to save as many kittens as possible as lots were starting to come in.
She said the little ones that were available for pre-adoption were very young, and needed to stay at Mangawhai's Helping Paws until they were 10 weeks old.
First option for adoption will be given to families on the waiting list.
Kelleigh Rudolph from M.A.D (Mission Animal Desexing) in Whangārei said Northland was really bad at dumping and getting rid of unwanted kitten.
Some sadly died from hunger and sickness or have had to be euthanised, she said.
"They usually slow right down during winter but because we've had warm winters in New Zealand, some of them still litter. The worst time for littering is around Christmas and New Year," Rudolph said.
Compounding the littering problem, she said, was that adoptions have slowed down because those who wanted kittens have got them now.
