Hong Kong has begun battling against a third wave of coronavirus infections, as nine of 14 new cases on Tuesday were classified as local and the government escalated its Covid-19 containment strategy to launch a review of social-distancing measures and impose new requirements for domestic helpers.

Declaring the situation “very alarming”, health minister Professor Sophia Chan Siu-chee unveiled a series of fresh measures to counter the worsening Covid-19 situation in the city, including controlling the flow of people returning from higher-risk countries, and requiring maids to quarantine in hotels on arrival.

“Now within a short period of time, we have seen multiple local cases with unknown sources of infection. This is an important warning signal to us,” Chan said. “It reminds all people in Hong Kong that we should not drop our guard.”

Raising the spectre of a return to tough social-distancing curbs, Chan said “now comes the time for suppression” under the government's “suppress and lift” policy of ramping up restrictions again when the Covid-19 threat returns.

A senior health official warned in a separate press briefing on Tuesday that the city had entered its third wave of coronavirus infections.

“We are worried that there will be a massive community outbreak, with so many sources of infection,” said Dr Chuang Shuk-kwan, head of the communicable disease branch of the Centre for Health Protection.

The alarming increase in Hong Kong’s infected toll – which now stands at 1,299 with seven deaths – was recorded as serious doubts were also cast over the formation of “travel bubbles” with the city’s neighbours such as Macau and Guangdong province.

Chan said Hong Kong had so far carried out more than 360,000 Covid-19 tests, amounting to 48,000 per one million people. She pledged the city would continue to ramp up screening capacity, and expected to add 2,400 extra tests to its daily quota from next month.

As part of the government fightback against a resurgence, Chan said the government would arrange the orderly return of its residents from higher-risk countries, such as Pakistan and India, in consultation with consulates and ethnic minorities in the city.

Foreign domestic workers, mainly coming from the Philippines and Indonesia, would be required to take a Covid-19 test before coming to Hong Kong and provide a negative result to enter the city, where they must undergo 14-day quarantine in hotel accommodation paid for by their employers.

Members of sea crew, who have been exempted from quarantine and screening when arriving in Hong Kong, would be required to take a virus test before setting off for the city. Without a negative result, they would be turned away from Hong Kong.

Starting from Wednesday, those workers, together with aircrew who are also exempted from quarantine, would be required to submit deep-throat saliva samples on arrival at Hong Kong International Airport.

Chan said the government would also consider tightening social-distancing measures, such as the number of people allowed to attend religious gatherings.

Other restrictions for premises such as restaurants and entertainment venues might also be reviewed, such as lowering the capacity limit and imposing other infection control measures. Visits to care homes for the elderly would also be suspended, she said.

Accepting the fresh outbreak could be described as a “third wave” of infections in Hong Kong, Chaung said the chain of transmission was very strong in a city seeing new cases from different sources on a given day.

“Since last weekend, the local epidemic situation has changed quickly. The situation is very critical,” said Dr Wong Ka-hing, the centre’s controller.

Health officials also warned of a possible outbreak in a nursing home in Tsz Wan Shan, adding that all residents there would be quarantined at Hong Kong PHAB Association Jockey Club PHAB Camp in Pok Fu Lam.

An 85-year-old female resident at Kong Tai Care for Aged Centre Limited was among those confirmed as infected on Tuesday.

Three other care home residents are also suspected of having the virus, including a 79-year-old man and a 67-year-old woman, who have both tested preliminary positive. Another woman with signs of fever has been sent to hospital.

As on Tuesday night, a medical source confirmed four staff from the same care home had tested positive and were being treated in United Christian Hospital.

“Perhaps there is an outbreak in the care home, although we are not sure of the source of infections yet,” Chuang said.

Among the five new local cases, where the source of infection could not be traced, was an IT worker at the Hospital Authority who visited Disneyland earlier this month.

Another falling into that category is a chef in his 40s who works at a restaurant in Shek Mun. His wife, son and daughter, who have mild symptoms, have also been sent to hospital for surveillance.

The spate of new local infections of unknown origins could push back the establishment of health codes and travel bubbles with neighbouring regions, Chuang said.

“If we can't even contain the spread of the coronavirus ourselves, then how can we expect other areas to cooperate with us?” she said.

Infection clusters might also be emerging at two Hong Kong restaurants, officials said.

Three cases recorded on Tuesday were linked to Bun Kee Congee and Noodle Foods in Ping Shek Estate, Choi Hung, where two staff were earlier confirmed as infected.

The latest infections are a 58-year-old taxi driver who visited the venue and his 14-year-old son, a pupil of CCC Rotary Secondary School in Wong Tai Sin who ate the takeaway food, as well as a 28-year-old man who lunched there.

Another two cases confirmed on Tuesday were linked to Sun Fat Restaurant in Jordan. A 68-year-old male waiter at the eatery tested positive and was a passenger of the 58-year-old taxi driver who also got infected.

At least nine education institutions linked to some of the new cases, including primary and secondary schools, said on Tuesday they would suspend face-to-face classes to minimise the risks of contagion.

They included CCC Rotary Secondary School and the Hong Kong Academy for Performing Arts, both reporting one infected student. The other seven involved instances where a relative of someone at the institution was infected, or teachers and parents had come into contact with Covid-19 patients.

Responding to the requirements for maids travelling to Hong Kong, Chan Tung-fung, chairman Hong Kong Union of Employment Agencies, said they were acceptable as most agents had already tightened measures for incoming domestic helpers a week ago.

A care home operator said they had not received any details from the government on the total ban of visits.

Edna Yeung Oi-shan, programme director of elderly residential and day care at Christian Family Service Centre, said they had already planned to restrict visiting arrangements in the wake of the new cases.

Noting it was the first time the government had fully suspended such visits, she said: “We will comply with the total suspension if the government provides the details.”