for 4G, only band 3, 1800Mhz avaiable in NZ and all 3 company had bought them for 4g network, and government will start selling 700Mhz next years.
for 3G, all 3 company use 2100Mhz in major city, but telecom use 850Mhz in rural while other 2 use 900Mhz.