Goblin trees, dolphins and echoes of Captain Cook on a cruise into Fiordland

Heritage Explorer slides on glassy water away from Milford Sound towards the open ocean. "The swell's only up to here on a seagull," cheers Captain Dave Barraclough, tapping his forearm with two fingers. "Almost calm enough for water skiing."

The albatross gliding past the wheelhouse at exactly that moment must be the portent of doom for, soon, a banshee's wail of maritime fury is sweeping across this raw-boned, ice-sculpted frontier. Our 30-metre vessel is pitching on the relentless Southern Ocean and some passengers are feeling queasy.

But, on the outer deck, my heart gives a little lurch. We are buttressed by blueish mountain peaks all the way to the sea-misted horizon and a squadron of white-capped albatross, skimming the ocean like Sunderland flying boats on reconnaissance, are almost at touching distance.

I cannot remember a more beguiling view of nature as deity.

Fiordland National Park is part of the Te Wahipounamu South West New Zealand World Heritage Area and it is not a place for the faint-hearted or the ill-equipped. Few people live in this inhospitable tip of the South Island, yet there is little appreciation for the sheer scale of early European settlement or the persistent struggle that began with Captain Cook's arrival in 1773.

"People say the Southern Ocean makes the North Sea look like a mill pond," continues Barraclough, bearing southwards for Bligh Sound (Hwea). "It's certainly the most challenging place I've worked in New Zealand, and I've been sailing Fiordland for 15 years."

Cook mapped labyrinthine waterways without satellite imagery or depth sounders, just sextant and compass and chronometer, inscribing ink on parchment. His charts are the genesis of our voyage today.

"No country upon Earth can appear with a more rugged and barren aspect than this doth," Cook wrote at first sighting. "From the sea for as far inland as the eye can reach nothing is to be seen but the summits of these rocky mountains, which seem to lay so near one another as not to admit any valleys between them."

The early settlers arrived in vessels about the same size as ours packed to the gunwales with people, pigs, and poultry. By 1795, more Europeans had entered Dusky Sound (Tamatea) than the rest of New Zealand, but they did not stay long.

Everything here is hard - the rocks, the seasons, the very logistics of survival - unless, like us, you're aboard an 18-cabin expedition cruiser with an international cohort of 12 inquisitive travellers.

These Australians, New Zealanders, Americans and Britons have been drawn by tales of Maori legend and European misadventure to dream of Fiordland for much of their lives. I have not. My last encounter was a dismal experience over days of rain falling with machine-gun rapidity on the Milford Track (Piopiotahi).

This journey is different. Over the next 10 days, we will navigate nearly all of the 14 glacier-carved fiords slashed along 12,600 square kilometres of pristine wilderness, bound for the semi-mythic waters of Dusky and Doubtful Sound (Patea), with six crew members anticipating every need.

Our resourceful chef inspires dinner-time deliberations over succulent venison tagine and baked blue cod before we retire to cabins just metres from the sea. Feather pillows and an ensuite bathroom are not to be underestimated but they are comforts that pale in comparison with the unfolding glory and grandeur of nature outside the window.

In the flawless calm of Bligh Sound, we are assailed by a playful pod of bottlenose dolphins, their blows vaporising as spectra in bright morning sun. "They're late today, usually here at quarter past," quips Barraclough. "Everything happens at quarter past."

On another day, at George Sound (Te Houhou), there's a chance to stretch legs on the shore. We pull onto a beach deep with polished stones clanking like delft underfoot as we step into a forest glade. It smells of mud and wet wood and Easter orchids and, up ahead, there's a hut. Its occupant stands shirtless at the only door.

"Just don't look 'em in the eyes," Barraclough had warned, but I cannot avert my gaze. The hunter's face is poxed by the plague of sand-flies. Itchy bites are all to show for weeks of damp isolation on his last day of hunting the wapiti (elk) that still lurk within these woods. The beasts liberated at the head of George Sound in the early 1900s - a gift from US president Theodore Roosevelt - have proved elusive.

Time passes on a rigidly flexible itinerary cruising from Doubtful Sound to the tranquil embrace of Dusky Sound, where Cook first encountered Maori on his second voyage of discovery. Mist slumps into the saddles of Wet Jacket Arm and bird songs drift across the bays.

"Here it is," the captain says, "one of my favourite places."

"Why here?" I ask, since every sight in Eden equals the last.

"It's the mood of it," he says, finally.

Barraclough commands with a refreshing lack of hierarchy. He's a versatile mariner and hunter, as skilled at unhooking a thrashing three-metre shark from a fishing line as he is steering tender past a rookery of splashing seal pups in a secluded creche. When not at the helm, he's clearing away the coffee mugs, or drying the dishes. We are already underway one morning when I flush him from the galley. "Who is steering this vessel?" I ask. "We'll stop eventually, eh?" he winks.

I would stop forever at Moose Lake, in Dusky Sound, were it not one of the wettest places in New Zealand. Putting on raincoats and gumboots, we clamber into the tender, then walk along a waterlogged track splattered with purple fungi and filmy ferns, tiny under towering forest canopy. Some of the beech trees, estimated to be 1000 years old, have surrendered limbs upholstered by heavy blankets of moss and fern, yet still others stretch into clouds.

Our guide, Mathieu, gestures to "The Goblin Tree", a monumental figment of Tolkien's imagination that actually exists. A New Zealand fantail (piwakawaka) flits about his shoulders. Weaving further enchantment, Mathieu whistles so many birds from the trees, even a white one never intended to be white. It isn't albino. It's a leucistic tomtit (miromiro), an almost comically spherical bird, like a fidgeting snowball in twiggy branches up ahead.

Captain Cook arrived in these forests to find them bristling with birds, including the world's only flightless parrot, the owl-faced kakapo. The crew ate the birds in great quantities: "It was not uncommon for them to perch on the barrel of the gun in our hands, already loaded for their destruction," wrote astronomer William Wales.

Since then, introduced pests have ravaged many species of ground-nesting birds over decades, but the islands in Dusky Sound embrace one of the most ambitious ecological restoration projects in the world. Populations of birds have been brought back from the brink of extinction although the war against reviled possum, rat, ferret and stoat is not yet won.

We bow beneath branches to a muddy clearing to the edge of Moose Lake. The water is mirror-still, lacquered by light, mountains swimming in their own reflections. As it was in the beginning. As Cook would have seen it.

Despite its name, there are no native moose in New Zealand. Ten Canadian moose were released in the Fiordland as part of a misguided attempt to establish a population for hunting in 1910. Some people believe they are still there but we return to Heritage Explorer without adding to the tally of unconfirmed sightings since the 1950s.

The sea rearranges itself among many small islands and we drop anchor in a pocket of jade beside the lonely outpost of Pigeon Island. There are no roads here. No boats either. We recognise the prints of the flightless kiwi, a nocturnal bird of beloved weirdness and vulnerability about the size of a chicken, but miss it probing leafy humus with its five-inch bill. Instead there's a mouse, staring back at us with mute incomprehension, scuttling with pink feet into tidal flotsam.

Our guide-led forest walks always bring forth something of curiosity: the rare boisterous kaka (forest parrot) or the red-eyed weka (a naughty flightless brown bird with a big personality). Ocean swells with red-billed gulls and shy albatross are book-ended by sheltered inlets with feathery waterfalls veining sheer granite, seemingly split with an axe and ready to slide into sea.

"Cool, eh," says Barraclough, steering the vessel as close as can be.

"Is it good or bad to see an albatross?" I ask.

Drama in the landscape reaches its crescendo when two Scottish doctors unintentionally capsize their craft. The water is metallic cold, dark as stout, but help is at hand and they are hauled back into the tender streaming like wet dogs."My wife said three fateful words which no man wants to hear: 'You're in charge!" exclaims Hercules, laughter booming across the bay. Is now the time to mention the mighty shark just released from a fishing line on Heritage Explorer, I wonder?

The raw edge of dripping wilderness somehow crystalises joy. "Belting rain, gale force winds, reminds you that you're alive," confirms Barraclough.

It's strange to think that our final port of call, so remote, was intended to be New Zealand's first capital. There is nothing left in the short-lived township of Cromarty in Preservation Inlet apart from the rusting remains of mining machinery and the only privately owned property excised from the National Park decades ago.

Kisbee Lodge is a rambling museum of dead wild things: a cavernous hunter's lounge filled with horns, hides, fossils and shells. A castaway couple live here as caretakers for three months at a time. Every day is different: cod fishing one day; deer hunting the next.

Journeys to far-flung places onboard small vessels accompanied by expert teams are more popular than ever so there's a well-rehearsed passage for a quick exit out of the Cromarty wilds.

We stand in a green patch, watch a helicopter drop from hypnotic sky, then lift high above fiord and mountain. Jittering towards Te Anau for the drive back to Queenstown, there's a bird's-eye view of Heritage Explorer and I'm grateful that we cannot speak above the rotor-rackety din.

I'm already wistfully missing the snug, dry feel of the boat with its mantra: "Please secure loose items in your cabins and don't forget to take seasick medication".

The writer was a guest of Heritage Expeditions