Despite the country's best efforts at containing the situation, Singaporeans must be mentally prepared that the number of cases from dormitories will continue to rise in the coming days or even the coming week or so before it starts to stabilise, National Development Minister Lawrence Wong said at a media conference yesterday.

This is partly due to the fact that many of the workers in the dormitories had very mild symptoms, leading to a delay in detecting Covid-19 infections among them.

In the interim, they continued to go to work, maintaining the chain of transmission in their work sites and back in their respective dormitories, said Mr Wong, who co-chairs the multi-ministry task force fighting the Covid-19 outbreak.

There is also a greater spread of the virus in dormitories due to the large number of workers living in close quarters, he added.

"It is very likely that the virus spread had been going around for some time in the dormitories, and we are now seeing all the indica-tors of it."

Health Ministry director of medical services Kenneth Mak noted that the sharp spike of 287 cases yesterday comes as the authorities have embarked on active case finding among workers, and are swab testing them in dormitories.

"Many of the cases that tested positive in this category were, in fact, workers who have very mild symptoms or were well," he said.

The numbers, particularly those linked to dormitories, may stabilise over time as the new circuit breaker measures take effect, said Health Minister Gan Kim Yong, who also co-chairs the task force.

Manpower Minister Josephine Teo said the authorities have also been working hard to introduce new measures in the dormitories to contain the spread of the virus.

These include transferring workers to alternative sites so that dormitories become less densely packed, and stepping up cleanliness and hygiene in the dormitories.

When workers with symptoms are detected, the authorities will make every attempt to isolate them and prevent them from mixing with other workers within the dorm, on top of testing them for Covid-19, said Associate Professor Mak.

Those who have not yet tested positive but remain symptomatic will also be separated, he added.

Mr Wong said: "We do have a comprehensive strategy and measures in place, and the agencies are now working around the clock to execute and implement them."