Marlborough produces around two-thirds of the country's wine — visit for the breadth. Central Otago is the world's southernmost wine region; its pinot noir is the calling card. Hawke's Bay is older, warmer, and the home of NZ syrah. Martinborough, Waipara and Waiheke are smaller, walkable, and built around boutique cellar doors.
Most cellar doors offer a flight of five to seven wines for $10–$20, often refunded against a bottle purchase. Many of the best are open by appointment only — book ahead, especially for vintage tastings or vineyard tours. Lunches at winery restaurants are a national institution; reserve a week out in summer.
Hire a driver or book a regional wine tour — most regions have one or two operators who know the smaller producers. In Marlborough and Hawke's Bay, cycling between cellar doors is genuinely lovely; bikes can be hired in town.