The shelter was under-resourced to deal with expanding cat numbers in Dunedin.
The population boom was a mix of domestic, abandoned and feral cats, she said.
She had approached the council and it had not acted on her plea for help.
''This is a massive problem and no-one will help.''
The council needed to support the organisations trying to tackle issue, she said.
''One organisation is not going to be able to do it on their own and it's only going to get worse and the cat population is going to grow and grow.''
SPCA Otago animal manager Grace Hepburn said she wanted a Dunedin City Council bylaw restricting the number of cats a person could have.
Otago SPCA inspectors were called last week to trap and remove 20 cats from a Dunedin woman, Ms Hepburn said.
The woman had not given the cats any attention so they were not used to people, she said.
The shelter was looking for volunteers to come to the shelter to spend time with the ''scared'' cats to try to make them adoptable.
''They're nice and they're not going to hurt anyone but they need that human interaction.''
Ms McSkimming said 20 cats was a small number compared with some cases reported to the shelter.
A Hampden man called the shelter recently panicking he could not control his growing clowder of 40 cats.
Council environmental health manager Ros MacGill said there were no council bylaws relating to cats and no bylaw was planned.
But if a cat was deemed a ''health nuisance'' the council could take action under the Health Act.