SINGAPORE - Passengers aboard the Quantum of the Seas cruise ship have reacted calmly to news that a guest had tested positive for Covid-19 on the third day of their three-night voyage.

Those whom The Straits Times spoke to said they were aware of the risks when they signed up, and have been comforted by the ship's safety measures and handling of the situation so far.

Ms Janice Leong, who is on board with her three-year-old son, said she was awoken by the captain's voice crackling over the intercom at 2.45am on Wednesday (Dec 9).

"I thought I was dreaming," said Ms Leong, 30, of the abrupt announcement that the ship would be returning a day early. It is currently docked at the Marina Bay Cruise Centre, as contact tracing efforts are ongoing.

The Singapore Tourism Board said the affected passenger is an 83-year-old male Singaporean.

Those determined not to have been a close contact of the affected guest will be allowed to disembark late on Wednesday evening. They will be required to monitor their health for 14 days, after which they will undergo a swab test.

The Ministry of Health later said the man's original polymerase chain reaction sample retest and a second fresh sample test both came back negative. Another test will be conducted on Thursday to confirm his Covid-19 status.

Ms Leong, a freelance writer, said she is not overly worried because of the strict safe distancing protocol aboard which saw, among other things, measures to discourage close contact and intermingling between groups of passengers.

A passenger who gave his name only as Mr Quek said he was "quite alarmed" by the early morning announcement, as it was not immediately clear whether the infection had spread.

An update at about 8am however, confirmed that the patient's close contacts had tested negative.

"That gave us some assurance that the case had been contained," said Mr Quek, 42, who is self-employed.

He added that he was surprised a fellow passenger had tested positive, given the mandatory pre-boarding testing and low number of community cases in Singapore.

Passengers, who have been confined to their rooms since the morning announcement, say they have been well fed and given water, though they are eager to disembark.

Mr Muhammad Rezal Ramli said his family of four was given "two rounds of breakfast", along with several large bottles of water.

"I think eight people can eat the amount of food we have right now," he joked.

Mr Rezal, 40, said he was not surprised by the news of an infection on board, though the trip's early end was disappointing. The family's first cruise had been enjoyable thus far, he said.

"We always go overseas every school holiday period; travelling is quite important to us as a family. So when there was this chance to go on a cruise and get the kids to do some activities that are different from what we have on a normal staycation, we thought why not."

Mr Rezal, a student development officer at Singapore Polytechnic, said the safe management and contact tracing measures on board reassured him that his family is unlikely to have been infected.

Passengers are required to check in when accessing different parts of the ship, with some activities requiring temperature taking, he said, adding that staff on board also enforced mask wearing and safe distancing between groups.

"Even if we get the disease, it is not something that we can complain (about) because we are aware of the risks," Mr Rezal said.

Like other passengers, he said the experience will not deter him from taking cruises in future.

"I think it's definitely your luck... I have friends who had gone on previous cruises with no issues."

He noted however that the three-day window between the testing of passengers and embarkation may have presented a gap during which the virus could have been picked up.

Passengers said they took a Covid-19 polymerase chain reaction (PCR) test at the Raffles City Convention Hall last Friday before setting sail on Monday.

Royal Caribbean's guidelines state that all guests must be tested within 48 to 72 hours of boarding as well as at the end of their cruise.

Ms Ameline Yan, who is on the cruise with her husband to celebrate their wedding anniversary, said she had specifically booked a room with a balcony because of the possibility of an infection on board.

The plight of the Diamond Princess cruise ship made headlines around the world earlier this year, after passengers were quarantined off the coast of Japan for several weeks, with many complaining about inadequate food and a lack of fresh air.

More than 700 passengers and crew members were eventually found to have been infected with the coronavirus.

In Singapore, Genting Cruise Lines and Royal Caribbean International were given the green light to offer "cruises to nowhere" starting in November, with a reduced capacity of 50 per cent as well as strict safety measures and infection protocols.

Ms Yan, 29, said she and her husband took additional precautions during the cruise, such as eating during off-peak hours and avoiding areas that attracted crowds.

Quantum of the Seas had 1,680 guests and 1,148 crew members on board the ship when it left for the cruise.

While passengers have been told they will likely be able to disembark in the evening, Ms Yan, who works in real estate, said she is not anxious.

"They're feeding us, giving us water, and we are in a balcony room, so I think we have quite good ventilation."

As for cruising again in future, she said: "I feel like it is still safe, because these are risks that are present anywhere, even in shopping malls... It wouldn't stop me if the proper measures are taken.

"And I would say that they were taken quite seriously (on this cruise)."