Hanmer Springs is a little town with 750 inhabitants. Although it's small size is the main hot spring resort in south island. This springs has been commercial used for more than 120 years. Spa are straight in the city centre. I prefer hot springs in nature and such you can find in southern island as well. City lays at 380 m. First white man arrive around 1859. AS it is spy resort prices are higher.
Besides relaxation in a city you can climb up to Mt. Isobel 1 319 m. Return hike took me around five hours. There is nice view from the summit. You can try bungee jumping in canyon circa 10 kilometers from town. For winters visitors is arranged sky resort.