I don't understand the 'economic growth at all costs' mentality. Both sides of the political spectrum have been driving high migration numbers.
If you look in the stats, it's not all brain surgeons either. Dairy workers and truck drivers feature too.
When you look at geography, the only substantial flat land in NZ is in Canterbury, Waikato and BOP. We could expect these to be the places to boom over the next wee while.