About 10,000 foreign workers in essential services have been pulled out of dormitories while others staying in them have been barred from leaving the premises from yesterday until May 4.
They cannot go out even for work, said Manpower Minister Josephine Teo at a virtual press conference yesterday.
This latest measure applies to workers of all companies, even those given permission earlier to operate in the current circuit breaker period from April 7 to May 4.
Mrs Teo said the new restriction "was something we had planned for, and now we're going to implement it". She also said the Ministry of Trade and Industry will notify the affected companies that have to suspend their operations.
"We know that there are going to be some adjustments to be made by the companies, but we seek the cooperation of both the employers and workers on this new condition. It is a necessary measure to minimise the risk of transmissions."
The measure took effect from 11.59pm yesterday, said a Ministry of Health statement.
It will apply to all dormitories, including the larger purpose-built ones as well as factory-converted dormitories and on-site temporary quarters.
Employers must continue to work with dormitory operators to ensure the well-being of workers in the dormitories, including taking care of their food and other daily needs, the statement added.
Workers in essential services who have moved out of dormitories are staying in alternative abodes, such as vacant Housing Board flats, floating hotels and military camps.
Safe distancing measures have been implemented at all purpose-built dormitories to prevent intermingling of workers, and medical posts have been set up so that they can report sick without having to leave the premises.
With the Muslim fasting month of Ramadan starting on Friday, Mrs Teo said the inter-agency task force, set up earlier this month to handle the outbreak in dormitories, has coordinated with caterers and dormitory operators to provide pre-dawn and break fast meals.
"This is very important to our Muslim friends and we want to ensure they're properly taken care of when Ramadan begins."
With the increasing number of coronavirus infections among workers in the construction sector, the authorities announced last week that 180,000 construction work permit and S Pass holders and their dependants were to be placed on stay-home notices from Monday until May 4.
Mrs Teo said her ministry decided to do this as contact tracing had indicated that transmissions at common construction work sites may have contributed to the rise in the number of infected cases.
"So this is something that we have taken as an added precaution and, during the period of the stay-home notice, enforcement officers will conduct regular and random checks."
These checks may include making phone calls or sending text messages to the affected workers who must respond, she added.
Earlier yesterday, Prime Minister Lee Hsien Loong said in a live address to the nation that the circuit breaker period will be extended by another month to June 1, with more workplaces to be closed to further reduce the number of workers keeping essential services going.
Addressing the impact on migrant workers, he said the Government will step up medical resources in dorms to protect the health of the workers.
This includes housing mild coronavirus cases either on-site, in a separate facility within the dorm, or in community care facilities elsewhere.
And he added that the Government will make sure that those who need active treatment receive immediate attention and are sent promptly to hospital.
"We will also pay special attention to the older workers, who are more vulnerable. We are pre-emptively moving them to a separate dorm, where they can be monitored more closely," he said.
As of yesterday, 28 of the 43 purpose-built dormitories in Singapore have known clusters. Also, there are at least 16 clusters at smaller factory-converted dorms.
Mrs Teo said workers have been understanding of the measures implemented, and she thanked them for their cooperation.
"If we are able to follow through with this... coupled with the measures taken at the dormitories, we have a real chance of breaking these channels of transmission."