I want to take advantage of the Qantas kids fly free program. We are US ex-pats trying to see this part of the world before we head back. Should our NZ trip (we only have 4-5 days) consist of Auckland mainly, then Wellington? How to break it up? And we are going in June - any suggestions? Thanks!

Suppose how old are the kids? may come into it and/or their interests too.
But either way 4-5 days ain't really enough to warrant splitting up and NZ is cooling well by June and more so the further south you head.

There's quite a bit of interesting touring/activities to the north of Auckland - they fib a bit in calling it the winterless north but it is not too bad weather wise and you may be interested in wineries, mail boat rides, farm stays, Bay of Island cruise/overnighting for dolphins, sand dune tobogganing etc.
http://www.warkworth-information.co.nz/ being not a bad place to start.
There's a heap of different web sites that you'll find farm stay references on, http://www.accommodationinnewzealand.co.nz/homestay.htm seems to be a reasonable one for full range of accomodation.

For a defacto cheap one, I can recommend a hostel that is actually a lovelly old farm house on a working farm - www.bbh.co.nz and have a look at Kahoe Farm - they have twin/double rooms and only a very small number of other guests at any time, maybe none in June and Tony an Italian will knock you up a wood fired pizza and find a good bottle of red for you.
http://www.travelplanner.co.nz/ also has a heap of info and do a Ctrl click on distances and then click link on next page and you get a handy map.

There's what they call the twin coasts tour if you want to follow it when heading north or do something similar, up eart coast and back on the west, ferry across Hokianga Harbour and stay at Masonic hotel in Rawene - http://rawene.co.nz/

Unless you have a special interest in Wellington, it may be that your kids would enjoy scenery rather than cities.

Consider a stay in AKL, then Rotorua, Coromandel, Waitomo, or Northland.

What about Northland? Drive out to Cape Reinga (NW tip of the North Island and take a bus day trip that runs you out to the very tip (DO NOT try to do this yourself!). You either go there or return via what is known as 90 mile beach. You drive right along the beach. Unforgettable!

I agree. Hire a car and focus your attention on the area around Auckland. Depending on what interests you and how much driving you want to do, I suggest that you look at the Bay of Islands/Northland region, Coromandel Peninsula and/or down to Tauranga and Rotorua.

We are planning a trip on Quantas in June as well and never heard of the kids fly free program. I plan to purchase the tickets tommorow, Wednesday, so can you give me some info?? Thanks!

Gabriella.
Check it out at qantas.com