MADANG, PAPUA NEW GUINEA — When our cruise ship arrives in Papua New Guinea, smiling kids paddle out in dugout canoes and entire families line the impossibly lush, palm-fringed shores waving and singing.

It's not just that the locals are friendly; our arrival is a rare occasion. It takes three days just to sail here from Australia, which means few tourists ever visit. But we've got the time. One hundred and sixteen days, to be exact. And we're not alone.

Extreme cruising – from six weeks to six months in duration – is one of the fastest-growing niches of the cruise market. According to the Cruise Lines International Association, which represents the 24 largest companies, the number of North Americans spending two weeks or more at sea rose 25 per cent in the past three years. There are more than a dozen world cruises in the offing next year. Several cruise lines are also adding multiple “grand itineraries” of up to 100 days that explore a continent or an ocean in detail.

“It's like an ongoing party,” says Cornelius van de Graaff, who has spent winters sailing since 2000. The 72-year-old from Toronto says he and his partner have tried condos, but they can't compare to a change of scenery every day. And long-term cruises foster a kind of floating community. “Not to have to sign for drinks makes the bars very sociable places.”

SUCH A LUXE JOURNEY

Of course, such holidays come at a price that might turn some travellers sea-green. The list rate for a suite on the Regent Seven Seas' Voyager is $114,000 for a 116-day trip. A two-storey penthouse on the Queen Mary 2 is $205,000 for a 90-day world circuit.

But passengers do get what they pay for. New ships such as the Voyager are built with all the comforts of a (very) nice home: Suites have walk-in closets, balconies and top-of-the-line bedding; meals include Kobe beef and champagne and caviar brunches; and there's a staff of hundreds to cater to your every need.

All of which could explain the repeat business. Regent Seven Seas offered its first world cruise five years ago as an experiment. But the itinerary proved so popular that many of the 700 passengers on board this year are regulars, and the ship is already nearly booked for next year.

Canadian snowbirds are particularly loyal customers. World cruises, which most often start in early January and last through April, are an alternative to wintering in a tropical condo or resort, says Mary Jean Tully, chairman of The Cruise Professionals.

Of the 332 passengers who did this year's full world cruise on the Crystal Cruises ship Crystal Serenity, 18 per cent were booked through her Mississauga agency and many have put down deposits for 2009.

“I think cruising is a whole lot easier than the winter months we've spent in Bermuda or Barbados, “ says Mary Alice Gammon, of Oakville, Ont., who has become a repeater along with her husband, Ted. “We were never catered to in a hotel like we are on a cruise.”