It occurs to me that, if the next election leaves NZ First holding the balance of powers, that the two largest parties would do well to consider an alternative.
The economic policies of National and Labour (free trade, mixed economy, independent central bank) are broadly the same. They differ mainly in emphasis - National wants to cut taxes, Labour to improve services. I suspect that neither Brash or Key really want to wreck the NZ economy by driving the budget into deficit (as their advertised policies undoubtedly would) - should they win the election look out for a claim that Labour left a "hole" in the accounts making their tax cuts impossible for several years (!)
NZ First have rather different views - if they can be said to have an economic policy it's Muldoonism - attempted autarchy and "redistribution through inefficiency".
So a Labour/National coalition would make sense for both parties (of course I personally would prefer Labour/Green). I wonder if either major party has ruled out a coalition with the other?