Is two weeks enough for New Zealand?
Yes, two weeks is enough for a strong New Zealand trip, but not for the whole country. A focused South Island route, or a carefully edited north-plus-south trip, will usually beat a frantic national lap.
Answer
Two weeks works when the cuts happen early. A South Island route around Christchurch, Aoraki/Mount Cook, Wānaka or Queenstown, Fiordland and one coastal or West Coast extension can be excellent. A two-island version can also work, but it needs discipline: perhaps Auckland or Rotorua, then a flight south for Queenstown and Fiordland, rather than trying to thread every place together by road and ferry. New Zealand punishes the itinerary that treats each drive as a scenic bonus and every stop as a one-night obligation. The better question is not whether two weeks is enough; it is whether the route leaves space for clouds, tiredness, grocery stops and the view you will want to pull over for.