The tai tais and their young male instructors shimmy, maskless and close together, their dance club a delightful escape from a world ravaged by a pandemic.

Little did anyone suspect that some of them had caught - and were spreading - the coronavirus.

Now, Hong Kong is paying for that lapse.

The city's dance clubs - known as playgrounds for its tai tais or ladies of leisure - are in the spotlight after they were blamed for what Chief Executive Carrie Lam called an "ultra-large cluster" of Covid-19 infections that sparked the fourth wave in the territory.

More than 600 cases have so far been linked to the cluster, accounting for nearly 10 per cent of all infections.

Videos of these dance clubs circulated widely online show dozens of middle-aged women, in shimmering dresses or ruffled skirts, hair neatly coiffed and earrings gleaming under the roving lights, keeping in step with their visibly younger male counterparts in tight shirts and fitted vests.

Many of these men are paid handsomely for their lessons and company, with some even illegally ferried into Hong Kong from mainland China, local media said.

Some of the instructors, who cover salsa, ballroom, tango and other classic forms of dance, teach at multiple studios, with premises rented specifically to host such get-togethers, thereby facilitating the spread of the disease.

Several members of Hong Kong's high society have tested positive for Covid-19 as the latest wave throws the spotlight on their exclusive social circles.

Billionaire Rossana Wang Gaw, 75, who chairs the listed property development firm Pioneer Global Group, fell ill after visiting Starlight Dance Club in the Wan Chai district last month.

Other well-known names linked to the cluster include former actress Tse Ling-ling, 64, the ex-wife of Lai Sun Development chairman Peter Lam Kin-ngok; as well as Mr David Chiu Tat-cheong, 66, who owns Hong Kong Cable Television and chairs property conglomerate Far East Consortium, and his wife Nancy Chiu Ng Wai-ping, 64.

Ms Tse has clarified that she was not part of the dance group but that she came into contact with an infected friend during a mahjong session.

Mr Chiu and his wife told the media that they were diagnosed after a private dinner at a friend's home that included an infected person from the dance group.

Local papers have gone into overdrive with news of the coronavirus wreaking havoc on the city's rich and famous.

Some did not pass up the opportunity to be salacious, highlighting in particular the large age gap between the women and their instructors, even going so far to insinuate impropriety between them.

The South China Morning Post quoted a dance enthusiast, identified only as Mr Ip, 63, as saying: "When dancing with the teacher, female dancers are treated like a princess on the stage."

He also claimed that some of his female friends had hired speedboat services to ferry dance teachers from Shenzhen to Hong Kong, despite the closure of the border between the two cities.

Critics say the tai tai dance cluster lays bare an uncomfortable truth: Many of Hong Kong's rich people care little for the lives and well-being of their less well-off compatriots.

Administrative assistant Elaine Lai, who is in her 30s, lives with her husband and two-year-old son just a few minutes' walk from the Wan Chai dance club.

She said: "If they had any decency, they would have maintained social distancing, or at least put on masks.

"We cannot afford to fall sick. If we stop working, the food will stop coming in too and the landlord will kick us out."

But there were others who were more forgiving.

Ms Sandra Wong, a corporate communications director in her 40s, said: "People can be inconsiderate, whether they are rich or poor. In the case of the tai tais, they should have kept their masks on or postponed their dance activities."

She added: "But I also think that the owners of the venues should be penalised as they shouldn't have allowed such big gatherings or let people go maskless on their premises."

Most, however, could not help but note that the premises were allowed to stay open for the elite to party, despite rules requiring social distancing and masks to be worn elsewhere.

Many livelihoods and the economy are bearing the brunt.

As a result of the new surge in cases, nightlife venues, mahjong parlours and theme parks have once more been forced to shut, restaurant dine-in hours and capacity are limited again, and public gatherings are now restricted to two people.

What would have been the world's first quarantine-free travel bubble between Hong Kong and Singapore - an attempt at normalising air travel - was halted due to the resurgence of Covid-19 in the territory.

Much of the blame may lie with the government rather than anyone else, dancesport athlete Sam Ng suggested in a column published on local news site Stand News.

"Perhaps the failure to contain the coronavirus should not be blamed on the behaviour of the Hong Kong people, but rather, government policy rife with loopholes," he said.

"Dancing isn't a sin… So what if the age gap between the dance partners is huge?

"The elderly woman who wants to dance may be widowed and unable to find a partner. What's so wrong with hiring a much younger instructor...

"Must she really take the trouble to find an 'appropriate' 80-year-old dance teacher for herself?"