There's a few options you could look into. We have a travel sim, for those traveling to NZ and wanting to use our network. Plans and information on travel sims can be found: https://www.vodafone.co.nz/travel-sim/
Alternatively, you could look at one of our prepay options, which obviously doesn't lock you into a term. Check out https://www.vodafone.co.nz/prepay/myflex/ for more information on our prepay plan. You are able to dial the data/mins/txts up/down.