But Erika Richter, the senior director of communications for the American Society of Travel Advisors, an industry group, said that demand for cruises, which had been on an upward trajectory before news of the coronavirus broke, was off from 10 to 15 percent according to some advisers.

Not surprisingly, cruises in Asia and the Pacific were especially hard hit. Alex Sharpe, president and chief executive of Signature Travel Network, a consortium of 7,000 travel advisers said, “New demand for these cruises is very low currently” and that spring sailings were “unlikely to sell from our market.”

“If the industry doesn’t get its arms around this it could affect customer confidence in China toward cruises for a very long time,” said Mr. Hardiman, of Wedbush Securities.

China has been one of the travel industry’s biggest growth markets in recent years, and, trips in the Asia-Pacific region make up about 10 percent of the industry, according to the Cruise Lines International Association, a trade group. Between 8 and 9 percent of passengers on cruise lines represented by the trade group are from China, Macau or Hong Kong and the number of ships deployed in Asia grew 53 percent between 2013 and 2017.

A growing number of ports across the Pacific, from Busan, South Korea to the New Caledonian ports of Lifou, Mare and Isle of Pines, are banning cruise ships. Hong Kong has been closed since Feb. 6.

Passengers say that rather than trying to accommodate them, the cruise companies have been uncommunicative and unhelpful. Maranda Priem, 24, of Washington, D.C., and her 53-year-old mother, from Minnesota, were supposed to be aboard the Norwegian Jade, a 2,200-passenger ship operated by Norwegian Cruise Lines, which was originally scheduled to depart from Hong Kong on Feb. 17 for a cruise stopping in Singapore, Vietnam and Thailand.

As her concerns about the coronavirus grew, Ms. Priem repeatedly emailed and called the company asking if she could switch to a different cruise or receive a refund or future credit. Her requests were denied. In an email on Feb. 4, Roxane Sanford, coordinator of guest relations for the cruise line, reminded Ms. Priem that “mainland China does not include Hong Kong, Macau or Taiwan,” and added that, “Regrettably we are unable to proceed with cancellation and refund.”