One place I will definitely go is Kaikora, to do whale watching. Whales migrate around New Zealand’s islands in set patterns, even going in and out of the Cook Strait, so if you want to see right whales, sperm, or humpback, this is your place to do it. There are also killer whale, and orcas, and dolphins.

http://www.naturallykaikoura.co.nz/kaikoura/WhaleWatch/

Off the Kaikoura coastline is a marine environment so rich in nutrients that it attracts some of the most magnificent creatures with which we share our planet. At the top of the list is the Giant Sperm Whale that can grow up to 20 metres and weigh over 50 tons. These whales can be seen all year round making Kaikoura one of the most popular whale watching locations in the world.

In addition to the Sperm Whale a number of other species may be seen, depending on the season, as they follow their migratory route.

This unique marine experience also provides an opportunity to sight New Zealand Fur Seals, Dusky Dolphins, the rare and endangered Hectors Dolphins, and a wide variety of seabirds including the Royal Albatross.
Once you have had your whaling adventure, you can head back to Picton. It is near the head of Queen Charlotte Sound near the north-east corner of the South Island. You can walk the most amazing nature trails, swim with dolphins, visit the Seahorse Aquarium and the maritime museum, a fascinating step into the whaling industry which still thrived in the area until the 1950s.
One thing is for certain, there is a huge number of things to do and see in New Zealand, and once you have visited you can’t wait to go back. I had two glorious weeks, and it was nowhere near enough.
If you want the best of all worlds on your vacation, sun, surf, nature and culture, plan a vacation to New Zealand.