You don't often read that headline... but as thr main kitten season in New Zealand has not been underway long, most of those available at this SPCA are too young yet to go to a new home.
By December there would be an abundance of kittens. "We'll be inundated, so please be patient. It's just a demand and supply issue."
If you are getting a kitten, especially a female one, please be responsible and have it speyed....before it has a litter! They can be operated on very young these days - usually when they reach about 1kg in weight as a rough guide. You don't have to leave it until they are 5-6 months old, but if you do, they are likely to be already pregnant.
Sad but true...