How to lose weight? Call home from a phone booth in the Marquesas Islands of French Polynesia. Outside it's a sultry 30C. The booth's a sauna and you heavily perspire as you describe your whereabouts:

"I'm on Nuku Hiva in the Marquesas Islands, a three-day sail northeast of Papeete and a hauntingly beautiful world away. "There are cloud-piercing peaks and plunging cliffs thrashed by the sea. Mangoes hang from the trees like golden globes. Waterfalls hurtle into fertile valleys. Small communities sprinkle around the bays and flowering bushes blaze with colour.

"And our ship is not just any old ship. Aranui III is a freighter that takes passengers along for the ride. She's a lifeline for the Marquesans. The villages turn out in force to greet her arrival while the cargo is craned over the side. Anything from 4WD cars to dog biscuits. It's barged ashore where there isn't a pier. Copra and tropical fruit from the islands is loaded back on-board.

"There are about 160 of us on-board from various countries. The flushest have top-floor suites with big balconies. The budget-conscious bunk down in a lower deck dormitory. And moi? No complaints. The cabin has its own bathroom and doors that open to waist-high bars. All the better for leaning out over the Pacific. We seem to have the immensity of the ocean to ourselves. But gotta go before I dehydrate in a phone booth. Wish you were here ..."

And it's out into the relief of a silken breeze where new friends from the ship are waiting. Adventurous Spanish senoritas, Sofia and Nekane. Droll Greg from Sydney, a photographer focusing on images of tattooed Marquesans, ancient man-size stone tiki and sites of former human sacrifice and cannibalism. Marquesan tattoos are the finest in French Polynesia and the biceps, backs and sometimes faces of some of the Aranui crew are strikingly adorned. An inspired Belgian passenger books in for a tattoo at our next port of call.

Linguistically and culturally there are frequent reminders of the links between the New Zealand Maori and the Marquesan people, whose ancestors settled the islands about 2000 years ago. In his absorbing on-board presentations, British film-maker and author Peter Crawford traces the migrations of the great Polynesian seafarers from their Asian origins. In 1595 a Spanish navigator named Medana became the first European to sight the islands, naming them Las Marquesas de Mendoza after a Peruvian viceroy. But to their Polynesian inhabitants the Marquesas have always been known as the Islands of Men, in reference to their mysterious tiki gods. The Marquesan population and culture are regaining strength, having been decimated from the time of European settlement in the late 18th century.

The Aranui makes nine island stops during the 14-day voyage and whale boats are lowered to take us ashore. There are visits to weather-beaten maae (marae) guarded by resilient tikis in the spiritual silence of the forest. We hike up mountain tracks _ god, how it can bucket down in the tropics.

And just as suddenly the clouds pull back to unveil the spectacle of razor peaks and lava spires of Ua Pou Island and of the Bay of Virgins (the name amended by the missionaries from its phallic original, or so the story goes). Rain or shine, wiry septuagenarian passengers from Santa Barbara don't miss a single hiking opportunity to view the brooding beauty of the Marquesas.

Outside a small church on the verdant island of Tahuata a man leads his pig into the waves for a swim. Together they frolic before settling once again into friendly communion in the shade of the church veranda. I pray the relationship will not end on the barbecue, and turn my thoughts to the wild horses roaming free on the island of Ua Huka. Brought from Chile in 1856, they outnumber the island's 500 residents.

We swim in balmy water, savour the scent of sandalwood and splurge on stone, wood and tapa cloth handicrafts _ collectors' pieces are half the price of those in Papeete. The hospitable Marquesans serve feasts of fish marinated in limes and coconut milk, of fried breadfruit, shrimps, grilled lobster, roast pork, banana puree and luscious mango. To the accompaniment of drums they perform electrifying dances. Without missing a beat, liquid-eyed children follow their moves from the sidelines.

Life on-board complements the shore visits. The ship's bar turns almost nightly into a dance party, courtesy of the Aranui band _ members of the musically infused Polynesian crew. Ukuleles strike up below on the crew deck and, late into the night, their harmony drifts out over the water like musical conversation. Passengers who began the voyage as tense as stretched rubber bands have succumbed to the South Seas rhythm and infectious laughter of the crew. After being wowed off her sling-backs by a dancing crew member, a much-mellowed mademoiselle from Paris has booked into Tahitian dance lessons on-board and turns up wearing flower-patterned wraps, bone pendants and a tiare flower behind her left ear.

Making new friends comes easily on a ship with the human scale of Aranui 111. I meet mustachioed Gheorghe, the ship's Romanian engineer and a cross between Hercule Poroit and Einstein. His on-board champion is Sophie Wong, the Tahitian-born sister of Aranui 111's Chinese owner.

"Gheorghe can fix anything," she smiles with emphasis on the "anything". To the bemusement of Greg from Oz, Sophie is also intent on finding him a young wife among the passengers.

An earnest dinner companion is Heinz from Germany, who is enamoured of the backwards-flying tropicbird. Jovial Dutch couples rave about their swim at Anaho Bay on Nuku Hiva Island, the only bay in the Marquesas with a coral reef, and the alluring spot that inspired Robert Louis Stevenson's book In The South Seas after he sailed there in 1888. Nuku Hiva is also the island where, 38 years earlier, Herman Melville, author of Moby Dick, jumped ship at Taipivai. His novel Typee recounts his experience.

Dinners are stimulating in the company of Giorgio Ricatti, who holds a title as the world's most travelled man. Giorgio has clicked his way through 100 rolls of colour slide film during the voyage.

Diego from Argentina's comparatively modest camera has jammed while photographing the former home of French painter, Paul Gauguin. Diego is tracing the footsteps of the artist who moved to the Marquesas in an attempt to recapture the paradise he believed was being lost in Tahiti to missionaries and colonials. Gauguin died in 1903 on Hiva Oa, destitute and alone. But to the end he was a champion of the Marquesan people. We visit Gauguin's grave on Hiva Oa island and, in the same hillside cemetery, that of Jacques Brel, the popular Belgian singer who was also seduced by life in the Marquesas.

A passenger from France confides that her great uncle, a former mayor of Papeete, had been given paintings from his friend, Paul Gauguin. "In those days Gauguin's paintings were understood by few. My uncle's family probably tossed them out with the rubbish," she smiles ruefully.

Back on-board Aussie Greg and I invite two Marquesan crew to join our table for the final dinner of the voyage: Mahalo, a stevedore with the dignity of a chief, and Kera, head of the ship's laundry by day, band leader by night. The Polynesian crew of the Aranui 111 help make the voyage one that none of the passengers is in a hurry to end.

If you go
* Aranui sails 16 times a year from Papeete to the Marquesas Islands.

* A round trip is 3493km via the pearl farming Tuamotu islands. Aranui carries 2000 tonnes of freight, is 355ft long and 51ft wide. She has 85 cabins, including 10 suites.

* Facilities include swimming pool, passenger decks, lounge, library, bar, restaurant and internet.

* Air Tahiti Nui flies several times a week from Auckland to Papeete.