The government has admitted it is struggling to contain the fifth wave of infections, fuelled by Omicron. But it has ruled out a city-wide lockdown.
A record 4,285 new cases were reported on Wednesday.
Chinese President Xi Jinping urged the local leaders to take "all necessary measures", in a rare intervention.
The comments may signal tighter controls in China's special administrative region, which pursues a zero Covid policy - but without the strict mass testing and lockdowns seen in mainland China.
