Passengers stuck on a cruise ship being quarantined in Hong Kong are beginning to worry that lax controls on the boat and a lack of information puts them at risk of being exposed to the deadly coronavirus.

"We are in quarantine, but everyone is still walking around," Edgar Chan, 28, said using WhatsApp. The software engineer, his sister and their parents have been quarantined on the World Dream vessel since Feb. 5, after it turned back from a planned four-day cruise to Taiwan. There's little information about what to expect or how to protect themselves, he said. "I am concerned about that. We don't know much about what will happen."

Passengers on the ship floating off Hong Kong have been biding their time with mahjong games, buffets and deck exercises. That contrasts with more aggressive controls for a boat in a similar situation in Japan, where health officials and Carnival Corp. have imposed strict isolation on thousands of passengers aboard the Diamond Princess off Yokohama.