"I think you'll find the regional places Jetstar are going to were never in danger of having services cut."
Yes, Air New Zealand was going to cut services to Palmerston North, now Jetstar is going there they are buying new aircraft and doubling services.
I am not sure if you remember the Kiwi Airlines V Air New Zealand War, Air New Zealand beat Kiwi Air into the dirt, and now they have nothing to do with "no frills travel" eg Freedom air, and Hamilton has no International flights.
Air New Zealand Lives for competition, if there is competition they kill it, if there is no competition have a monopoly and price gouge.
Hopefully with Jetstar coming into the regional market in NZ and possibly Qantas this will rattle ANZ.
Best Regards