Wellington, http://www.mjmarine.co.nz/ Maurice Dickie. Good, quality work
Auckland. https://www.facebook.com/NZ-Shipwrights-Ltd-100381874667427/ Jorn Douglas, 0276992674 good general repairs etc
Whangarei, https://www.facebook.com/search/top?q=twenty%2020%20marine%20ltd Richard Edlin, 021416531, Very good boatbuilder, designer, all material types.
Probably others, but if you talk to these guys, tell them Matt Paulin recommended them. You'll get a good honest deal from all three.