Health officials announced on Tuesday that another seven infections of the new coronavirus had been confirmed in the territory, bringing the total so far to 49, with some of the latest patients connected to previous cases.
These include the son and daughter-in-law of a 62-year-old Tsing Yi woman diagnosed with the illness, as well as the daughter-in-law's father.
A man living in the same block as the couple and his mother in Cheung Hong Estate had also come down with the illness, and the older woman's subsequent diagnosis prompted a partial evacuation of the building on Monday night.
Officials said five other residents of the tower block who had shown symptoms of the disease have tested negative and they have since been sent to quarantine camps to join the 200 or so of their neighbours already taken there overnight.
The quarantined residents will be allowed to return home if they once again test negative for the virus after a few days, officials said.
They also said that they were still working on the theory that a modified drainage pipe in the 62-year-old woman's flat could have led to her infection. She lives several floors directly below the man who had earlier been diagnosed with the virus.
Housing officials said three other public housing estates which have seen confirmed cases will now have their drainage pipes checked as a precaution.
Hong Kong University microbiologist Yuen Kwok-yung said there was no need for people to panic and the Tsing Yi block at the centre of the scare, Hong Mei House, is not in the same situation faced by Amoy Gardens during the Sars outbreak in 2003.
The failure of U-shaped water seals at the Kowloon Bay estate had allowed the spread of Sars, eventually affecting more than 300 people, of whom 42 died.
One of the other new cases announced by authorities at Tuesday's press briefing involves somebody who works with one of the 11 family members confirmed to have the illness following a Chinese New Year hotpot gathering in Kwun Tong.
Another of the patients is a 59-year-old man who works in a church in Siu Sai Wan, officials said.
The other two patients are a 66-year-old man who lives in Tuen Mun and a 71-year-old man from Tseung Kwan O.