I am finding that while Air New Zealand markets "Business Premier" as being "like first class but at a business class fare" what it actually is is a product for which you "pay a First Class sized fare but only earn Business Class points".
Meanwhile Premium Economy fare levels are starting to approach other airlines' Business Class fare levels.
EXAMPLE 1
Emirates First Class return Brisbane to Auckland = $1459
Emirates Business Class return Brisbane to Auckland = $1069
Air NZ Business Class return Brisbane to Auckland = $1774
Air NZ Premium Economy return Brisbane to Auckland = $1176
In other words (and this is true on some long haul fares too), Air NZ Business Class costs more than Emirates' First Class, and Air NZ Premium Economy is comparable to other airlines' Business Class fare levels.
EXAMPLE 2
From London to Australia most airlines will sell a Business Class ticket for around 2200 pounds if you know where to buy it. Air NZ charges 3200 pounds for Business Premier and 1900 pounds for Premium Economy. So Air NZ Premium Economy costs 86% of other airlines' Business Class fare, while Business Premier costs almost 50% more than competitors' business class offerings.
EXAMPLE 3
Similarly, from Australia to the USA you can buy Business Class fares from $4000 (China Airlines), $5000 (Thai) or even the very long way via the United Arab Emirates for $6000 (Emirates or Etihad). Meanwhile Air NZ charges $10,000 in Business Premier or nearly $4000 in Premium Economy.
From Melbourne or Brisbane to Honolulu, Qantas Business Class costs $3979 while Air NZ Business Class costs $ 6399.
The pattern, which I hope is coming through loud and clear, is that Air NZ "Business Premier" fares are now set at First Class levels - but without First Class points or amenities - and that while Premium Economy fares are only around half of the Business Premier fare they are actually coming in at DOUBLE the discount economy fare (not the 25% premium the airline originally promised) and around 90% of what other airlines's Business Class products cost.
My 20c worth as someone who flys LHR - AKL 4-5 times a year NZ are invariably the cheapest option for a Y+ offering and this is always cheaper than a business class fare unless you get a window where NZ have sold all the lower price Y+ seats and there are still discount Business seats (even had an example where I got business for only £400 more than Y+ on NZ).
As for business the only airline flying out of Heathrow that regularly beats NZ for Business LHR-AKL is Emirates and even then very infrequently.
My feeling would be that outside NZ, NZ are always very price competitive.