SINGAPORE - More than 1,600 passengers who were aboard the Royal Caribbean's Quantum of the Seas cruise ship disembarked on Wednesday (Dec 9) night in an hours-long process that began nearly 12 hours after the ship returned to Singapore a day ahead of schedule.

The four-day cruise to nowhere was cut short by a day after a passenger tested positive for Covid-19.

However, two subsequent tests conducted by the National Public Health Laboratory came back on Wednesday night with negative results - suggesting the initial test could be a false positive.

Another test will be conducted on Thursday to confirm his Covid-19 status.

By the time the test results were announced on Wednesday night, the disembarkation process was well under way, with the first passengers seen leaving the ship, berthed at the Marina Bay Cruise Centre, at around 7.50pm.

Passengers had their temperatures taken before leaving the vessel. They were placed in groups - comprising 10 to 25 people - with specific departure times to reduce crowding. The last groups disembarked around midnight.

Moving in an orderly fashion with their bags, they made their way to the cruise centre, where they had to take an antigen rapid test and were then free to go.

Passengers were told they would be notified within an hour if their results were positive.

Flight steward Leon Chen, 31, who disembarked at around 8pm, told reporters that the process went smoothly.

He said it took just 10 to 15 minutes to leave the vessel, including the time required for the antigen rapid test.

"There were many attendants and staff who helped to guide us from our room to the gangway, and the antigen test wasn't as uncomfortable as a normal swab test. We don't know the results yet, but if anything is wrong, they told us that they will call us," said Mr Chen, who was on the cruise with his girlfriend Lim Jia Yee, 30, a flight stewardess.

Antigen rapid tests involve nasal swabbing. They can give results more quickly, are cheaper and are easier to administer than polymerase chain reaction (PCR) tests, although they are slightly less accurate.

Mr Chen said they would monitor their health in the coming days.

He said they were given a pro-rated amount for the night that they missed out on, and that they were satisfied with the refund. They were also given cruise credits with a year's validity.

Ms Lim said: "I don't think anyone expected this to happen, and they did respond quickly to the crisis. We are happy with the compensation that was given and the cruise itself was really exciting. It was handled well and we were kept informed and updated at regular intervals."

Civil servant Siti Zamiara, 43, who was on board the cruise with her husband and 15-year-old daughter, also said the disembarkation process was very efficient.

She said the experience would not deter them from taking cruises in the future.

Her husband, operations technician Reyaz Hamzah, 44, also said that they had "no regrets" about going on the trip.

Not all passengers got off without a hitch. Travel writer Heidi Sarna, 54, said she was told to be ready to leave at 7.30pm, but waited till 9pm to disembark.

"There was a bit of a bottleneck in the corridors on the ship. An attendant had to tell some of us to go back into the rooms, so that helped the situation," said Ms Sarna, an American who has lived in Singapore for 15 years.

On the negative retests, she said: "It's frustrating and disappointing that all this may have happened for nothing. But you also realise there's nothing you can do about it, and I can't fault anybody for this."

Though they were confined to their rooms since 2.45am on Wednesday, passengers said they were well taken care of.

Student development officer Muhammad Rezal Ramli, 40, said his family of four was given "two rounds of breakfast" and several large bottles of water.

"I think eight people could eat the amount of food we had," he joked.

He added that the cruise - his family's first - was enjoyable, though the early end was disappointing.

Teacher Kelvin Cheng, 31, who took the cruise with his wife and daughter, disembarked at 10.45pm. He was frustrated by the turn of events.

"This had been a long-awaited holiday for us, and we understand the need to adapt to safety measures if a case is detected. But now that this case has tested negative, it makes us question the reliability of the PCR test on board," he said.

Ms Ameline Yan, 29, who works in real estate, said she was not upset about the turn of events. "It was better to err on the side of caution... a minor inconvenience is better than if it had turned out to be an outbreak."

The Singapore Tourism Board said the affected passenger is an 83-year-old male Singaporean. His close contacts who have been identified and test negative for Covid-19 will be sent to a designated government quarantine facility.

The Quantum of the Seas is the second ship to sail from Singapore as part of a safe cruise pilot scheme by the Singapore Tourism Board.

The four-day voyage is the ship's second voyage with paying passengers. There were 1,680 guests and 1,148 crew members on board when it left on Monday night.

Royal Caribbean has cancelled a four-night cruise set to depart on Thursday.