NEW YORK — U.S. tour operators are planning to send a record 4,000 or more travelers to Antarctica, prompting calls for strict government regulation to protect penguins, other wildlife and the very fate of the frozen continent.

“The number of tourists visiting Antarctica has more than tripled in the past five years,” said Bruce Manheim, a Washington activist of the Environmental Defense Fund who calls existing controls inadequate.

Antarctica has become a “hot” travel destination for the 1990s, beckoning older Americans seeking more adventure than Europe and hoping to see a fragile frontierland visited by only a privileged few in their youth.

They are fueling fresh growth in the adventure travel industry, an estimated $1.3 billion-a-year phenomenon.

About 800 American tourists traveled to Antarctica in 1988, 3,000 in 1989, and tour operators expect at least 4,000 in the December-February summer season. Manheim says it could reach 5,000.

“There’s clearly a trend toward these type of expeditionary visits to remote places in the world,” said Manheim.

He filed an appeal Tuesday with the government urging more regulation.

“We are not trying to prohibit tourists from going to Antarctica, we just think tourism is something that has to be regulated carefully,” he said.

Concern began mounting after the January 1989 grounding of the Argentine naval ship Bahia Paraiso in which an estimated 175,000 gallons leaked into marine habitats, killing seals, penguins and other marine life. The vessel remains at the site off Palmer Station with some oil in its tanks.

Particularly worrisome to critics are the plans of Ocean Cruise Lines of Fort Lauderdale to send the largest cruise ship in years to Antarctica, the 460-passenger Ocean Princess.

Rates begin at $3,895 per person for a double-occupancy cabin on its three wine-and-caviar cruises, which are selling briskly. The first round trip from Buenos Aires, Argentina, begins Dec. 22.

Manheim’s appeal is urging the government to place strict controls on helicopter flights near wildlife sites, guidelines on tourist observation of penguins and seals, and coordination of cruise ship visits to breeding grounds.

He said ships had made repeated tourist visits to the same wildlife sites, disrupting the breeding of seals, penguins and other birds.

“A year after Antarctica’s most significant environmental disaster, we still don’t have regulations to prevent similar catastrophes,” said Manheim.

The U.S. government responds that effective regulations are already in place.

“We have tried, and we believed we have dealt succesfully with the explosion of Antarctica tourism,” said Jack Talmadge of the National Science Foundation, which regulates U.S. activities in Antarctica.