Would you want AUS and NZ to unify?

cc_of_Oz is correct. There is provision in the Australian Constitution for New Zealand to become the seventh State of Australia should they want to do so. All that is required is for New Zealand to hold a referendum and if the people agree, they become part of Australia. Australia has no say in it, we made the offer at Federation and the offer still stands. It is up to New Zealand whether they join Australia or not but I don't think they will.