Beyond the crowds, New Zealand hides an island few travellers ever reach

I've spent a lot of time travelling around New Zealand and I've found that the further south you go, the more genuine people get," says Rhys Morgan as we drive out of the township of Oban. "And this is as far south as you can go - it's like stepping back in time 50 or 60 years."

I'm on Real NZ's Villages and Bays Tour, and there's no danger of getting stuck in a traffic jam as we explore Rakiura (Stewart Island) aka New Zealand's third island. Located 39 kilometres off the storm-battered coast of the South Island, it has fewer than 500 permanent residents and there's not a traffic light or roundabout to be seen.

But despite being overlooked by most tourists, this little slice of paradise has plenty to offer. The name means "glowing skies" in Te reo Maori, a nod to the aurora australis that are regularly visible this far south, and much of the island remains largely as it was when the Maori people first arrived 750 years ago. About 85 per cent of the island's 1750 square kilometres is protected national park, and that old-growth forest provides vital habitat for some of New Zealand's most iconic species.

Native birds have been able to thrive thanks to extensive predator control and strict regulations that include compulsory kiwi aversion therapy for pet dogs. These measures have been so successful that Rakiura is home to the same number of kiwis as the entire South Island, which is almost 100 times larger. As a result, this is the place to see New Zealand's loveable mascot.

Rakiura's extreme southern latitude results in short summer nights that prompt some of the 20,000 kiwis to venture out in daylight, but you're far more likely to spot them once night falls. And while tours like Real NZ's Wild Kiwi Encounter maximise your chances of seeing one in its natural habitat, they've been known to wander into locals' gardens and New Zealand's southernmost rugby pitch is often filled with tourists searching for these usually elusive birds after dark.

While there are still a few invasive species on Rakiura, the hundred-plus islands scattered around the coast are small enough that some have been declared completely predator-free. One of these is Ulva Island, an open sanctuary reached via a two-minute boat ride from Oban.

Four walking tracks cross the north of the island, which is home to scarlet-crowned kakariki parrots, plump kereru (wood pigeons) and playful Stewart Island robins that bounce behind tourists and search for bugs disturbed by their footprints. Giant kaka parrots emit hoarse, pterodactyl-like screeches that add an appropriately prehistoric feel to the island's ancient forest. "If you can put your arms around the trunk of a rimu tree it's about 300 hundred years old," says Ange Karaitiana, who leads Beaks and Feathers' Ulva Island Guided Walk. "Some of the bigger ones here are 1200-1500 years old."

Among the most endangered birds are mohua (yellowhead) - "you can see them on the hundred dollar bill, and the birds are even rarer" - and tieke (saddlebacks). Though there are only 2000 left in the world, Ange points out a pair within minutes of stepping ashore and for several minutes we watch these handsome black and chestnut birds flutter around the trees completely unbothered by our presence.

Rakiura has just 28 kilometres of paved road but almost 300 kilometres of walking tracks, and exploring on two feet is the perfect way to appreciate the island's abundant natural beauty. The three-day Rakiura Walk is one of NZ's iconic Great Walks and connects several of the backcountry huts dotted around the island, but there are plenty of less strenuous options closer to Oban.

The forest that covers much of the island helps to prevent soil runoff and keeps the surrounding waters unusually clear - from Oban's main wharf I can watch fish swimming through the kelp forests below. And though early European arrivals decimated the local seal and whale populations, the underwater ecosystems remain quite healthy.

Seals, sea lions and penguins abound in the nearby waters and the main industry outside of tourism is fishing. The best place to taste the local catch is Kai Kart, a food truck serving up freshly cooked fillets of blue cod and crispy golden chips that have developed a cult following. Rhys, who quips that he's been researching fish and chips for 70 years, proudly declares that "this is the best you'll find anywhere in the country."

The writer was a guest of Tourism New Zealand