HONG KONG, China -- Hong Kong may impose a China-style hard lockdown that confines people to their homes, authorities signalled Monday, with the city's zero-COVID strategy in tatters and bodies piling up in hospitals.

Two years of strict zero-COVID policies kept the coronavirus largely bay but a breakthrough of the highly transmissible Omicron variant exposed how little authorities had done to prepare for a mass outbreak.

Hong Kong leader Carrie Lam previously ruled out a citywide lockdown and instead has ordered all 7.4 million residents to be tested in March.

But in a U-turn, health secretary Sophia Chan confirmed on Monday that it was still an option.

Asked by a presenter at Commercial Radio whether a lockdown was still ruled out she replied: "No. We are still discussing."

"From a public health perspective, to bring out the best effect of compulsory universal testing, we need to reduce people's movements to some extent," she added.

Chan's comments came a day after Li Dachuan, a senior mainland official involved in a joint taskforce with Hong Kong authorities, described a lockdown as "the most ideal and best approach to achieve the best effect of universal tests".

- Bodies in hospital -

The revelation adds fresh uncertainty and anxiety for residents and businesses in a city gripped by the kind of chaos that was more familiar at the start of the pandemic.

Hong Kong has now recorded 193,000 cases and 636 deaths in the current wave since December 31.

That compares to just 12,000 infections and 205 deaths for the whole of the rest of the pandemic.

Hospitals have been stretched to breaking point for weeks and on Sunday officials revealed bodies are piling up at hospitals because mortuaries are full.

"At this moment, we face a problem of transportation of dead bodies from hospital to public mortuary," Hospital Authority chief manager Lau Ka-hin told reporters.

"That's why there are some bodies who were initially planned to be transported to public mortuary, but stayed in hospital."

- High mortality rate -

Hong Kong's seven-day average death rate is currently running at around eight per one million people.

That compares with five per million for the United States, 1.80 for Britain and 1.36 for Singapore which, like Hong Kong, initially opted for zero-Covid but shifted more recently to a mitigation strategy and reopening to the wider world.

Officials have revealed that 91 percent of those who have died in the current wave were not fully vaccinated.

The vast majority of the dead -- 92 percent -- are people aged 60 or above with the median age 84 years old as the virus rips through care homes in the densely populated city.

Despite ample supplies Hong Kong had a dismal vaccination rate among over-70s before Omicron struck.

China is now increasingly calling the shots on Hong Kong's response with the joint taskforce operating out of the neighbouring city of Shenzhen.

Mainland crews are working on constructing a series of temporary hospitals and isolation wards for the infected, although the current caseload far outstrips supply.

Among those advising the government is Liang Wannian, a senior mainland official that the South China Morning Post reported was arriving in Hong Kong on Monday.

Liang was a key architect of the successful two-month long lockdown in Wuhan where the coronavirus first emerged, a strategy China has continued to deploy in other cities as soon as cases are detected.

Wuhan's official toll was 53,000 cases and it took two months to suppress with a full lockdown.

Hong Kong has recorded that many cases in just two days and is also battling a much more infectious variant.