A building in Ap Lei Chau was locked down overnight on Saturday after a mutant coronavirus strain was detected.
Health officials said they aim to finish the lockdown of Mei Ka Court in South Horizons by about noon on Sunday.
Earlier, officials said they found no new Covid infections following an overnight lockdown at Ngar Tsui House at Hiu Tsui Court in Siu Sai Wan.
They said around 750 residents were tested during the exercise.