Covid-19 contact tracing app due in 2 weeks for New Zealand

Apologies for not reading all of the numerous comment threads about Australia's contact tracing app, which went live yesterday and already has over a million downloads according to the verge: https://www.theverge.com/2020/4/26/21237598/australia-corona... Quite a few comments to read in this HN submission: https://news.ycombinator.com/item?id=22986147

I'm wondering, for my fellows of you who think privacy is extremely important and oft neglected, what minimum criteria would need to be met for you to consider using the (NZ) app?

So far I've been comfortable with the measures the govt has taken and I think a contact tracing app could be an excellent tool to implement, short of the total collapse of our economy due to continuing lockdowns, or exponential spread of the virus and collapse of the medical system as is being seen in Japan. Or maybe we don't need an App at all and can avoid these scenarios.