all my 30 + years of surfing both the North and South islands before moving to Noosa I have never had problems with crowds (until I moved to Noosa lol)
oh Makarori is no secret, there are so many quality breaks North and South of Gizzy not to mention Mahia. There are so many surf spots on both coasts mostly accessible and if you know the conditions and prepared to drive you will score. As for an over abundance of surf tourist invading local spots, nah won't happen. NZ is to far off the beaten track.
ive never been to Bali, the place just doesn't interest me, I always travel back to NZ for surf, my next trip back will be South Island staying with whanau, Mangamanu, Kaikoura and CHCH beachies for surf. I lived in CHCH for 9 years before moving to Aus, so I still have my 5 mil wettie, booties and gloves lol.
Oh HB

Jaffas wont go further south when you have the Coromandel, Rags or Sandies up north. Gizzies to isolated, worth the roadie though.
stay stoked