Once you are automatically enrolled you can opt out so don't let that stop you getting a new job.
https://www.ird.govt.nz/kiwisaver/ki...t-of-kiwisaver
Odds are that you will live to 65 and well beyond so its a no brainer to stay in and at least put in the minimum 3% and collect the free 3% from your employer and the annual government contribution. Then put anything else into a fund that you can access when needed.