SYDNEY, Australia — A giant cruise ship is set to sail into Antarctic waters, changing the face of tourism in the world’s great wildernesses.

The Golden Princess, which can carry 3,800 passengers and crew and weighs 109,000 tons, is 10 times bigger than most of the cruise ships that ply Antarctica’s seas. Its first voyage in January will herald a new era in the commercial exploitation of the region.

“It will alter the whole complexion of Antarctic tourism,” a polar policy specialist at the University of Canterbury, New Zealand, and an official observer at Antarctic Treaty meetings, Alan Hemmings, said.

“This will undermine the ethos of small ships and small visitor numbers, which has prevailed until now.”

Once the domain of intrepid explorers such as Robert Falcon Scott, Sir Ernest Henry Shackleton, and Roald Amundsen, Antarctica is becoming increasingly crowded. An explosion in tourism, an American-built “ice highway” to the South Pole, an air link from Australia, and plans to establish more scientific bases are all part of a dramatic rise in human activity. The number of tourists visiting Antarctica has leapt in the past 15 years to 30,000 from about 5,000.

The arrival of big liners has prompted fears that, in the event of an accident, a rescue operation would be all but impossible in such an inhospitable environment.

“A vessel like the Golden Princess is not ice-strengthened and will be operating in a part of the world where there is poor hydrographical information,” Mr. Hemmings said. “You’d have to try to rescue nearly 4,000 people.”

British delegates at an international Antarctic meeting in Edinburgh in June lobbied to prohibit giant liners from the continent. The head of the British delegation, Mike Richardson, said that, if one sank or ran aground, it would create an “unthinkable disaster” on the scale of the Titanic or the Exxon Valdez. Other Antarctic cruise ships are typically former research vessels carrying up to 250 passengers.

A spokesman for California-based Princess Cruises, Julie Benson, said passengers aboard the 210-meter Golden Princess would “absolutely not” be exposed to any risk. The ship was fully equipped for the journey, she said.

“Princess maintains the highest safety standards for all our ships, wherever they may be deployed around the world.”

She also denied that the liner would pose any danger to the environment.

An environmental lobby group, the Antarctic and Southern Ocean Coalition, warns that “there is essentially no constraint on where you can go, what you can do, and how many of you can do it. … Mass commercial tourism has now arrived in the Antarctic.”

Flying to Antarctica may soon be an option — a privilege until now reserved for scientists. Australia has nearly completed a 2-mile-long ice runway near its Casey research station.