I suspect based on risk in NZ it will be a simple mask , its not an emergency room with confirmed Covid patients spluttering over everyone.
I guess it partly comes down to whether we should all be acting like we all have COVID or not. I don't think customers will be asked to wear a mask when getting their hair cut, because the one the hairdresser is wearing should potentially protect both people, as long as it is a proper type..Maybe they will be told not to talk, and to keep the mouth closed. The thing about hairdressers I have found, is often can't stop talking, as it is often a place where gossip spreads.
It will be interesting to see how they do it, and I suspect some customers may choose their hairdresser based on the PPE they use and how safe they feel. I certainly will be. I have caught a cold from a hairdresser before in the past, so it is something that I know is a potentially high risk activity .
But personally I think it is common sense that everyone should be wearing some form of mask when out, to partly to make it socially acceptable. Also all Asian countries that have been successful in getting case numbers right down, all use masks in public. This is also the recommended opinion of some NZ health experts on this.