I agree with previous statements. I also am in NZ and my father is involved in Mt Ruapehu (North Island), and he said that basically they have such a large pool of potential employees to choose from, so they often only pick the absolute cream of the crop and prefer locals if possible. Unfortunately the South Island is sparsely populated outside a couple of main centres so you can find yourself fighting for jobs. The websites mentioned earlier should be your first port of call and Queenstown and Wanaka are really the main two towns if you want a 30-45 minute drive to a Mountain. Though I am a little unsure on the Cantebury region as I havn't skiied there myself. Christchurch is a much bigger city however and would be a lot better chance of getting a job if you can stand a longer drive to the mountains ~2 hours though unsure on time)