The government on Thursday locked down a public housing block in Shek Kip Mei after sewage samples there tested positive for Covid-19.
Residents and recent visitors of Mei Wui House at Shek Kip Mei Estate must get tested and stay at home.
The government added that some residents there also recently tested preliminary positive for the coronavirus and there is a signficant risk of infection at the block.
Officials said they were hoping to complete the lockdown operation by noon on Friday.