Health authorities have reported that one of the confirmed Wuhan virus cases here could be a locally transmitted case, as the patient and his family had no recent travel history outside of Hong Kong.
Leading microbiologist Yuen Kwok-yung, from the University of Hong Kong, said if local transmission is indeed established, that could be very dangerous, and "Hong Kong can become another Wuhan".
Yuen said if it is the case, border restrictions must be ramped-up to reduce the flow of people, regardless of their nationality, coming to and from the mainland.
He said there were many virus cases in Guangdong province, particularly in Shenzhen, and so there was a high risk of getting infected there.
And Yuen suggested that anyone who crosses the border should stay there, to avoid bringing any viruses back to Hong Kong.
He also agreed that any patients who lie about their travel or medical history should be punished - an idea mooted by health secretary Sophia Chan on Saturday.