Inbound flights from eight countries, including India, are prohibited in Hong Kong

On Wednesday, Hong Kong ordered a two-week embargo on incoming flights from eight countries and reinforced domestic COVID-19 restrictions, citing fears of a fifth coronavirus outbreak in the city.

The new limitations were revealed as health officials scoured the city for connections of a COVID-19 patient, some of whom had been aboard a Royal Caribbean ship that had been ordered to return to port after being told to cut short its "cruise to nowhere."

Incoming flights from Australia, Canada, France, India, Pakistan, the Philippines, the United Kingdom, and the United States, including interchanges, would be barred from January 8 to January 21, according to Hong Kong leader Carrie Lam.

From Friday, the government will prohibit indoor dining after 6 p.m., and swimming pools, sports centres, bars and clubs, museums, and other facilities will be closed for at least two weeks, according to Lam. Cruises in the future would be cancelled.

"We`re yet to see a fifth wave yet, but we`re on the verge," Lam said.

By largely isolating itself from the rest of the world and imposing a strict and costly quarantine rule, the global finance hub has maintained a zero-Covid approach.

With the initial local transmission of the new Omicron type on Dec. 31, a three-month period without community cases came to an end.

Authorities have been scrambling since then to trace down and test hundreds of persons who had come into contact with a small number of Omicron cases. However, one case had no known connections, raising concerns about a widespread breakout.

"We are worried there may be silent transmission chains in the community," Lam said. "Some confirmed cases had a lot of activities before being aware they got infected."

A patient who danced with 20 buddies in Central Park on New Year's Eve inspired the most recent contact tracing campaign. Preliminary testing revealed that two of the other dancers, one of whom was a domestic helper, were positive.

For January 2, the helper's boss and eight other close associates embarked on a cruise.

Hong Kong has restricted cruises to short voyages in adjacent waters as part of its coronavirus limitations, with ships being urged to operate at reduced capacity and only admit vaccinated passengers who test negative for the virus.

The "Spectrum of the Seas" ship had roughly 2,500 guests and 1,200 crew members on board when it returned a day early. According to police, the nine close contact passengers were quarantined from the rest of the passengers on board, and preliminary tests conducted throughout the voyage yielded negative findings.

"Spectrum of the Seas is taking appropriate measures under guidelines by the Department of Health," Royal Caribbean told Reuters in a statement.

The nine close contacts were taken to a quarantine centre, while the rest of the passengers and crew will be subjected to a series of mandatory tests in the coming days, according to the government.

In a second statement, the government claimed that people who visited dozens of locations across Hong Kong around the same time as the close contacts of recent cases were handed compulsory testing letters.

The list included Victoria Park in downtown Hong Kong, the newly-opened M+ modern art museum, ferry terminals, restaurants, stores, and clinics.

According to Gabriel Leung, the head of medicine at the University of Hong Kong and a government consultant, the city likely has "five to 10 invisible transmission chains."

"There's no time to waste," Leung said. "We need circuit-breaker measures."