HONG KONG - Hong Kong residents have been urged to stay home as the city braces for what could be the worst Covid-19 wave so far, while the government announced a further delay of the launch of the travel bubble arrangement between the city and Singapore.

Speaking at her weekly press conference on Tuesday (Dec 1), Chief Executive Carrie Lam urged people to stay home and avoid unnecessary family gatherings.

"The next two weeks will be critical so unless necessary, I hope residents can stay at home, especially the elderly. People should avoid social gatherings even if at home," she said.

Mrs Lam noted that it has been announced that a hotline has been set up for the public to give tip-offs about private parties on yachts, and urged people to call the number if they see crowds at the piers so that the coastguards can follow up.

She added that the government is now looking at the possibility of raising the current fine of HK$2,000 (S$345) for individuals who breach social distancing measures.

On the further delay of the air travel bubble arrangement with Singapore, the Hong Kong government said parties "will review the arrangement for 2021 towards late December".

"Travellers who have already made bookings on designated flights during December 2020 may wish to contact their airlines and adjust the itineraries according to their own circumstances," a Hong Kong government spokesman said.

The first flight was originally planned for Nov 22, but both governments announced the delay on Nov 21. The authorities at the time said they would review the situation and decide by early December.

The extension did not come as a surprise, as the seven-day moving average of unknown local cases in Hong Kong as at Monday was 16. The threshold agreed by Singapore and Hong Kong is five cases.

A Hong Kong-based Singaporean, who wants to be known only as Ronny, 32, bought bubble flights to go home late this month, but is now "sitting tight" before he changes his flight.

He said he paid about HK$3,800, well over the HK$1,300 he usually pays for flights back to Singapore.

"But I bought the ticket knowing full well that things may change, and the bubble could burst any time," the media professional said, adding that he might change flights to next December which is the peak season.

He also said he might buy new tickets if he decides to go back in January.

"It's my practice to go back in January to celebrate my birthday, but this year I guess I will have to contend with two-person meals and perhaps a celebratory hike or two."

So far, Hong Kong has a total of almost 6,400 cases, including 109 deaths. The number of daily new infections has crossed 70 for more than a week.

This spike was led initially by a growing dance club cluster of more than 500, most of whom are tai tais and their young dancing instructors.

On Tuesday, health authorities said the city added 82 new cases, with 72 of them local and 23 with unknown sources.

Professor Ben Cowling, an infectious disease expert from the Hong Kong University, said he expected the fourth wave to begin sooner when measures were relaxed in September, as there is always a risk of transmission re-surging if infections are reintroduced.

"I think the priority now has to be to strengthen social distancing measures, taking reference from the measures that were effective in curtailing the second and third waves in March-April and July-August respectively. That includes recommending civil servants to work from home, and closing gyms and other leisure facilities," he said

In the past week, the government has made a series of orders, from mandating that dance club visitors go for compulsory tests to ordering patrons of specific eateries to go for the tests as the virus circulates.

From Dec 2 for two weeks, dine-in services will end two hours earlier at 10pm, with patrons capped at two per table. Bars, pubs, saunas, clubs, nightclubs and party rooms will remain closed.

All amusement game centres, leisure venues, museums, cinemas, theme parks, karaoke establishments, mahjong clubs and swimming pools must be closed.

Gyms, massage and beauty parlours can stay open but the number of patrons must be capped at two, while civil servants are to work from home and public gatherings limited to two people.

The tightening of measures comes as local transmissions, particularly among the city's rich and powerful, have spread like wildfire, initially with some socialites linked directly to the dance club cluster and later, expanded as they continued to mingle over meals and mahjong.