The Auckland SPCA has been inundated with kittens because of unseasonably warmer weather extending cats' typical breeding season.
It's calling for foster and "forever" homes.
Veterinary manager Dr Shalsee Vigeant said the autumn weather in May had led to a higher number of kittens.
"Cats normally start breeding during the warmer weather around October and it should start to slow as the mercury drops from April. This year we're just not seeing that.