Morgan is looking for a government decision and estimates NZ$100 million for the first year:
RadioNZ: CovidCard is a low energy bluetooth device the size of a credit card, that is designed to be worn on a lanyard around the neck when in areas such as public transport, workplaces, bars, restaurants, gyms, hospitals, large gatherings and events.
This seems like an excellent solution although I'd like to know more about it. At this point it seems like it's not exactly required with our current elimination strategy. Things could change and maybe it's best to be prepared even at this cost. I see this as a far better solution than phones, gps and scanning. Even many preschool kids can use these.