Cheap domestic travel in New Zealand

Milevalue highlights a great option for cheap domestic flights in New Zealand – Air New Zealands 'grab-a-seat' program.

Scott mentions that tickets can only be purchased for some of the last minute fares but it also leads into the regular booking workflow at Air New Zealand which can lead to ever lower priced tickets.

You will need to be a member of Air Points, NZ's loyalty program. You can sign up here and use the code JOINAP or FAIRY for a free signup. NZ is charging NZ$50 to be a member otherwise.

This looks like a great option for a flexible traveler in NZ especially if you need cheap one-ways. Most of us will book award flights directly to the NZ destination (i.e. Queenstown)
but if you run out of allowable stopovers this seems to be the way to go.