Hong Kongers stripped shop shelves bare on Tuesday as panic buying set in following mixed messaging from the government over whether it plans a China-style hard lockdown this month.
The latest disarray came as the city's top medical school estimated just under a quarter of all residents had been infected with Covid-19 since the start of the year.
Photos circulating on social media showed people had trouble finding a variety of items including meat, vegetables, frozen food, noodles, paracetamol and testing kits.
"We are like ants going home, grabbing a bit at one spot at a time," a woman, who gave her surname Wu, told AFP on Tuesday in a supermarket where most vegetables and meat had been snapped up.
One of the most densely populated cities on Earth, Hong Kong has supermarkets with limited backroom storage space. Apartments are also some of the smallest in the world, leaving little space to stock up.
The vast majority of Hong Kong's food is imported from mainland China and the current supply crunch has been worsened by cross-border truckers getting infected by the highly transmissible Omicron variant.
The financial hub is in the grip of its worst coronavirus outbreak, registering tens of thousands of new cases each day, overwhelming hospitals and shattering the city's zero-Covid strategy.
More than 190,000 infections have been recorded in the last two months, compared with just 12,000 for the rest of the pandemic.
Authorities plan to test all 7.4 million residents this month and isolate all infections either at home or in a series of camps that are still being constructed with mainland help.
City leader Carrie Lam had initially ruled out a mainland-style lockdown, where people are confined to their homes during the testing period.
But on Monday, health chief Sophia Chan confirmed it was still on the table.
Multiple Hong Kong media said authorities were planning a variety of lockdown options for the test period, citing sources.
The South China Morning Post said the current favoured option was a nine-day "large-scale lockdown" where most residents would only be allowed out to buy food.
Experts from the University of Hong Kong published new modelling data on Tuesday which estimated the current number of infections at 1.7 million.
They warned that mass testing should be delayed a month rather than under current plans when the wave would be at its peak with as many as 183,000 daily cases.
The coronavirus has killed at least 5,977,973 and infected over 437.7 million people since the outbreak emerged in China in December 2019.