The Royal Carribean International cruise ship Quantum of the Seas (center) is docked at Marina Bay Cruise Centre in Singapore on Wednesday. Photo: AFP

A passenger aboard a Royal Caribbean "cruise-to-nowhere" from Singapore has tested positive for COVID-19, forcing around 2,000 guests to be quarantined in their cabins and the Quantum of the Seas ship to return to dock on Wednesday.

Singapore has been piloting the trips, which are open only to residents, make no stops and sail in waters just off the city-state.

The global cruise industry has taken a major hit from the coronavirus pandemic, with some of the earliest big outbreaks found on cruise ships. In one case in February off the coast of Japan, passengers were stuck for weeks aboard the Diamond Princess with over 700 guests and crew infected.

"A guest was feeling unwell and tested positive for COVID-19...We are asking all guests to remain in their staterooms to prevent the spread of illness," the captain of the Quantum of the Seas told passengers in a video shared on social media.

"We kindly ask all guests with urgent medical or health situations like diabetes, heart disease etc to contact guest services," he said.

Confirming the positive test, Royal Caribbean said that all guests and crew who had close contact with the infected guest have subsequently tested negative for the virus.

"Emergency response plans have been activated according to guidelines including immediate isolation of close contacts, contact tracing and deep-cleaning of the ship," Annie Chang, director of the cruise segment at Singapore Tourism Board said.

Reuters