Pressure is mounting on Hong Kong officials to rein in the escalating Covid-19 outbreak that has popped the Singapore-Hong Kong travel bubble arrangement, with the territory's government tightening measures and making tests compulsory for some.

Live performances and dancing in bars and pubs will be banned, while premises such as party rooms for holding social gatherings will be forced to shut for five days from today to Thursday.

Business owners who breach these new rules can be fined up to HK$50,000 (S$8,665) and jailed for six months, the government said in a media release yesterday.

Chief Executive Carrie Lam restated early yesterday the health authorities' update in a Facebook post, saying the pandemic in the city has hit a "severe" stage. "Our priority now is to quickly cut off transmission through testing," she said, adding that testing of those deemed high risk will be ramped up and her team will seek to encourage more voluntary testing.

Officials also announced mandatory tests for those who have visited 14 dance premises - sites of the latest outbreak.

These measures came after Hong Kong yesterday recorded 43 confirmed cases - the highest daily figure in three months - of which 36 were local and 13 untraceable. This brings the tally in the city to 5,560 cases and 108 deaths. Another group of more than 60 people was found to be positive after preliminary testing.

Of the latest 43 cases, 21 were linked to Wan Chai district's Starlight Dance Club, which is at the centre of the dance group outbreak. This brings the cluster to 32, including eight instructors.

Dr Chuang Shuk Kwan, head of the communicable disease branch at the Centre for Health Protection said a couple of patients linked to the cluster had not been to the studios, indicating signs of "super-spreading".

Hidden transmission links were also detected in multiple districts including Wong Tai Sin, Mong Kok, Sham Shui Po, Tin Hau and Mid-Levels.

"The numbers are escalating, so the trend of increase is very alarming. We are very worried that a further increase in cases will happen, and it will be very difficult to control," said Dr Chuang.

The forced testing would be the first such move by the government after the new law kicked in last Sunday. People who refuse a test can be forced to take it and be fined HK$2,000. Those who ignore the order may be jailed for up to six months and fined up to HK$25,000.

Dr Lau Ka Hin of the Hospital Authority said about 4,000 beds, including those at a temporary medical facility at the AsiaWorld-Expo near the airport, will be available if the outbreak worsens.

Flights originally scheduled to start today under the travel bubble arrangement were suspended as the pandemic in Hong Kong escalates. Both governments had agreed to suspend the bubble flights for two weeks if either city reported an average of five or more local transmissions a day over a seven-day period.

For the seven days from Nov 15, Hong Kong recorded an average of 3.9 unlinked local cases, but with the further 60 preliminary positive ones, today's average would likely cross the threshold.

Content marketing executive Fairoza Mansor, 35, is among those disappointed by yesterday's turn of events as she is booked on a flight to Hong Kong on Wednesday.

She had decided to go ahead with the Nov 25 flight as she had to be back in the city for work.

"So I've resigned myself to the two-week hotel quarantine that Hong Kong has in place," she said.

Hong Kong-based marketing executive Susanne Liu, 43, has different concerns.

She is worried that the Singapore government might tighten rules for people arriving from the territory but said she "would keep going (to Singapore) even if quarantine is required" as she has been apart from her Singaporean husband for more than half a year.