“We have been watching very closely the trend of development in any part of the world, also apart from the Schengen area in Europe, so we will not exclude additional measures towards other countries,” Chui said.

Anyone arriving from the Schengen region, which has a combined population of more than 420 million, will have to undergo a mandatory self-quarantine for 14 days, starting from next Tuesday. Countries including France, Germany, and Denmark are covered.

Those arriving from the Emilia-Romagna, Lombardy and Veneto regions of Italy – the worst-hit country after China – face mandatory quarantine in government camps.

In addition, from midnight on Friday until next Tuesday, all arrivals from the Bourgogne-Franche-Comte and Grand Est regions in France, North Rhine-Westphalia in Germany, and La Rioja, Madrid and the Basque Country in Spain, would have to self-quarantine, and not be confined at government facilities as previously announced. The same will apply to arrivals from Hokkaido in Japan.

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Chui said many arrivals from listed countries would be quarantined at home because there were limited isolation facilities, and officers needed to prioritise who should be sent to the sites.

But Dr Ho Pak-leung from the University of Hong Kong urged the government to also impose quarantine restrictions on Britain.

Ho said he expected to see a surge in the number of confirmed cases in Britain in the coming weeks, considering that the government there had not adopted drastic measures to fight the pandemic.

“So many Hong Kong students now stay in the UK and there are hundreds of thousands of residents who have the right to abode in the country,” he said. “The Hong Kong government should better predict the situation and take more decisive action.”

Parents whose children study in Britain have already expressed concern, according to Angus Tang Chi-wing, director of HKIES Overseas Education Centre. The centre has received dozens of inquiries from concerned parents since the outbreak in Italy.

Tang said around 5,000 Hong Kong students study at private schools in Britain and there was no plan to suspend classes yet.

“As far as I know, more than 10 students came back from the UK to Hong Kong in the last two days,” he said.

He suggested parents discuss the situation with schools before bringing back their children ahead of the Easter holiday.

Chris Leung, 28, who is studying for a master’s at the London School of Economics, initially planned to return to Hong Kong in April to conduct research for his dissertation, and have a holiday.

But he has decided to stay in London as he is worried he would need to be quarantined or not be able to return to Britain to finish his exams in May and June.

“It’s hard not to get worried, but as long as I have taken the necessary precautions I think things are going to be all right,” he said.

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In York, an undergraduate student surnamed Wong, 20, said she would come back next week for the holiday. She said more classmates from Hong Kong wanted to return home, and believed the city had taken more measures to guard against the virus.

“In Hong Kong, people will wear a mask and not be discriminated against,” she said, adding that she was once called “coronavirus” by British teens in the city.

Meanwhile, the Hong Kong University of Science and Technology has suspended exchange programmes with mainland China, South Korea, Italy, and affected regions in France, Germany, and Spain, and said it would arrange for students to get back to Hong Kong soon.

Polytechnic University has strongly advised its more than 100 students in the Schengen region to return to Hong Kong.

AFS Intercultural Exchanges, a non-profit organisation offering international exchange programmes, has terminated its programme in Italy and could do the same in other countries, depending on the situation.

The organisation has sent 60 students to European countries in the Schengen area this year.

According to the Travel Industry Council, about 540 people in 27 tour groups in Europe will visit or have been to Schengen countries and will return on or after next Tuesday, when the self-quarantine measure kicks in.

Alice Chan Cheung Lok-yee, its executive director, said travellers would be likely to undergo quarantine at home unless their itineraries could be adjusted. But she said that would be hard if their original schedule mainly covered Schengen countries.

“Some travel agents are trying to arrange for their tour groups to return earlier. However, it is also not going to be easy because many airlines have cancelled flights due to the recent drop in demand for air travel,” she said.

Meanwhile, restrictions for Hongkongers returning from South Korea will be revised so that arrivals from Daegu and Gyeongsangbuk-do have to undergo confinement at government camps for 14 days. Other Hong Kong returnees from the country can opt for self-quarantine.

Last month, the government banned non-residents from the country entering Hong Kong.

Health official Chui said the entry ban was imposed because South Korea had surging cases at that time, but the outbreak there was now mainly focused on two places and the trend had eased a bit, so they adjusted the measures according to the changing situation.

Additional Reporting by Elizabeth Cheung, Karen Zhang, Victor Ting, and Chan Ho-him