HONG KONG -- Hong Kong will deny entry of visitors who have stayed for over two hours in Britain during the past two weeks, effective from midnight Monday, to fend off a more infectious strain of COVID-19 virus reported there.

Secretary for Food and Health of the Hong Kong Special Administrative Region government Sophia Chan announced the decision at a press conference on Monday afternoon, adding that the new measure equals to a ban of all flights from Britain.

Visitors who have already arrived in Hong Kong will be required to stay at home for additional seven days and take another virus test after their compulsory quarantine in hotels ends.

As new and untraceable infections remain high, Hong Kong is at the most severe and crucial moment of fighting COVID-19, Chan said, calling on residents to reduce gatherings and remain alert during the upcoming Christmas holiday.

Existing social distancing measures will be extended to Jan 6, including closures of bars, compulsory mask-wearing and a group gathering limit.