Passengers on board the Royal Caribbean's Quantum of the Seas cruise in Singapaore, where a man tested positive for the new coronavirus, were allowed to disembark from the ship about 12 hours after docking on Wednesday morning, Channel News Asia reports.

The ship docked at Marina Bay Cruise Centre Singapore at 8:00am, a day ahead of schedule, after an 83-year-old male passenger tested positive for the coronavirus.

CNA observed passengers leaving the ship via an enclosed gangway shortly before 8:00pm. They were told that the process of disembarking would take place in batches.

Among the first to disembark were Leon Chen, 31, and Lim Jiayee, 30.

The process was "quite easy," said Lim, adding that passengers were guided through by staff members.

From clearing immigration to taking the coronavirus antigen test, the whole process took about 10 to 15 minutes, she said. Results of the test were expected in an hour.

Passengers have to take another polymerase chain reaction (PCR) test after 14 days, said Chen.

According to Chen, the captain told passengers at 2:45am that the ship would be turning back ahead of schedule, and the announcement about the man who tested positive was made after docking at about 8:00am.

Passengers had to wear "tracer wristbands" and keep the TraceTogether contact tracing tool on.

"They kept us updated every four hours, and even on board before the situation they had a lot of safety distancing measures in place to keep track of all of us," Chen told CNA.

Lim added that she was "quite panicked" after the announcement but the cruise operator handled the situation "very well.''

A passenger who was among the last batch of people to leave the ship at about 9.30pm said there was no safe distancing at one point.

"When they came and knocked on our rooms and asked us to proceed to the gangway, (there were) a lot of people, we were so surprised," Mdm Adeline Tan told CNA. "When I see this situation, I got a bit of a shock."

She added that there was a "jam" at the corridor and the lift, but that the situation was okay after that.

Three buses were seen arriving at the cruise centre at about 9pm. They were meant to ferry close contacts of the man who tested positive, according to traffic controllers.

Passengers on the Royal Caribbean's Quantum of the Seas cruise disembark at Marina Bay Cruise Centre Singapore on Wednesday, December 9.

Quantum of the Seas passengers leave ship in Singapore after virus scare