One preliminary Covid-19 case was found in Yau Ma Tei, while three close contacts in Mongkok were sent to a quarantine centre.
Anyone who was in a wide area bounded by Pitt Street, Tung On Street, Canton Road and Dundas Street in Yau Ma Tei was required to get tested by 2 am.
This was the second lockdown in nine days for some of the residents affected – authorities had sealed off a smaller area on Pitt Street and Tung On Street for mandatory testing on Tuesday last week, identifying one coronavirus infection.
Residents who had proof of a negative test result since Tuesday were not required to get tested again, though they were required to stay within the restricted area until the lockdown was lifted.