Want a sense of which way the 'net migration' picture is moving in NZ - read this story in the NZ Herald. NZ will have its day, though it might have to wait a few more years. The notion that you need an income of $150,000 to live in Australia strikes me as utter nonsense. The cost of food in NZ and Australia is better in Australia, particularly after the increase in the NZ GST to 15%. Maybe that was the final straw for the NZ government. They ought to have cut into welfare rather than raise the GST. Anyway, they might be wise to reconsider effectively taxing immigration...as they are driving migration to Australia.
You can rent a place in Artarmon, Sydney for $370 per week. If you are sharing, that is a modest $750 per month. You can therefore live comfortably in Australia for anything over $50,000. In fact most immigrants from NZ would be making $80,000 plus.