Singapore is taking strong steps to stop the virus from spreading within the country, using social distancing as a major line of defence. This is on top of tougher measures to prevent infections being imported from elsewhere.

Restrictions will be put in place for large-scale social, cultural and sporting events.

To limit the occasions large crowds gather in close proximity over a prolonged duration, all ticketed cultural, sports and entertainment events with 250 participants or more are to be deferred or cancelled, said Health Minister Gan Kim Yong yesterday.

For events that organisers are committed to, where they have sold tickets, for example, they must show that they have "satisfactory measures" in place in order to carry on with the events.

Large national events such as the May Day Rally and the National Day Parade may need to take on a different format, added National Development Minister Lawrence Wong, who co-chairs the multi-ministry task force on Covid-19.

As for large private functions and religious services, the ministers said these should try to reduce the number of people attending to fewer than 250.

Other safety measures include larger venues to prevent crowding, preferably with participants sitting a metre apart from one another, better ventilation, not shaking hands and getting contact details in case someone at the function has the infection and everyone there needs to be contacted.

There should also be temperature and health screening as people enter. Those who are unwell should not be allowed in.

People who have been invited should also exercise social responsibility and not attend if they are feeling unwell.

There is no magic to the 250 figure. Mr Wong said organisers should look beyond that number and consider the capacity of the venue, the duration of the event, and the nature of the activity.

"It's more complex than a single number," he said. "But to put each of these principles into a simple guideline is difficult, at the end of the day scale does matter.

"If you have a 1,000 to 2,000 people event, it's very hard. There are not many large venues in Singapore. When we took all these into consideration, 250 is a good benchmark."

The purpose of social distancing, the Ministry of Health said, is "to limit large crowds gathering in close proximity over a prolonged duration".

The ministers also urged employers to reduce close contact of their employees by staggering work hours, having enough space between work stations, and tele-commuting or video-conferencing where possible.

If there are on-premises meetings, seats should be spaced apart.

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So far, activities at community centres have been stopped for a fortnight, mosques are closed for five days and the Catholic Church is continuing its suspension of masses.

Precautions must also be taken at public venues.

Tourist attractions and entertainment venues such as casinos, cinemas, museums and theme parks should limit the number of visitors at any one time.

Similarly, indoor sports centres like gyms could limit the number of patrons and increase the frequency of cleaning.

Dining places should set their seats at least a metre apart.

At the press conference, the ministers were - for the first time - seated a metre apart, and reporters were put in staggered seats with a metre separating them.