Mrs McDonald says cupcakes are a simple yet effective way to raise funds for the cause.
"There's something special about a cupcake," she said.
"They are yummy and delicious and are helping to fight animal cruelty."
Last year's event raised more than $200,000 nationally and the SPCA is hoping for an even better result this year.
"Our SPCA receives virtually no government funding so it relies heavily on fundraising events such as Cupcake Day to continue to provide shelter to an overwhelming number of animals in need of protection," she said.
About 3000 animals are brought into the Whangarei SPCA every year and the service investigates more than 900 animal abuse complaints annually.