Though the circuit breaker will end after June 1, restrictions on activities such as dining in and meeting friends and most kin will remain as Singapore enters the first phase of reopening its economy.

This will disappoint people but the measures are necessary to avoid any risk of the coronavirus flaring up again, said National Development Minister Lawrence Wong at a virtual press conference yesterday.

"The feeling of being cooped up at home for a long period of time is starting to have its effect on people... But I hope we can all maintain our discipline for a while longer," added Mr Wong, co-chair of the multi-ministry task force tackling the pandemic.

He warned that "if we were to open up too quickly and allow all these social activities to restart, there is a risk the virus will flare up, and we might see many more cases and clusters forming".

The minister made the point when outlining the three phases of reopening after June 1.

Health Minister Gan Kim Yong, fellow co-chair of the task force, said it could take at least four weeks to exit the first phase and enter the second one, which is a transition stage that will see the resumption of some social activities.

The reason for adopting this timeframe is that Singapore will, by and large, need to observe the situation for two incubation periods - or 28 days - after it rolls back the existing circuit breaker measures, he said.

But it is not set in stone. Adjustments will be made along the way as the situation evolves.

"We don't have a crystal ball to see what's going to happen... But at the minimum, we are not likely to make major shifts in the first four weeks," said Mr Gan.

In deciding on the right time to move into the second phase, the Government will not just rely on the number of new cases, he added.

Rather, a "whole basket of factors" will be considered in assessing risk, including the nature of transmission of new cases.

The task force will also consult professionals to help judge whether Singapore is ready for the second phase, he added.

"It is not 'yes' and 'no', it's not a table that you tick off and then say, oh, we have passed all these and therefore we can move into phase two," he said.

Should the number of cases soar and big clusters emerge in the first phase, some of the circuit breaker measures will be reintroduced in a targeted way. But this hinges on which sector has a higher risk profile, he added.

The minister also said Singapore is prepared to see a rise in the number of cases initially as people interact more. But if, among other things, the number of cases remains low over a sustained period, then Singapore can consider going into the second phase, he added.

Mr Gan warned that the second phase could also last for several months - three months, six months or longer - depending on the situation.

Mr Wong said there will be two stages in the second phase.

The first stage will kick off with lower-risk activities.

These may include some limited social activities, including letting people gather in small groups and dining in at restaurants.

In the second stage, higher-risk activities - such as events, entertainment and attractions with bigger crowds and close contact among people - will be assessed for reopening, he added.

In the third phase, when Singapore will be in a state of stability, new controls and safeguards have to be put in place until a vaccine is found, said Mr Wong.

It is not a return to life before Covid-19, he stressed.

While activities such as going to a theatre, cinema or place of worship will likely be possible during this phase, limits on group size and safe distancing measures will remain, he said.

Similarly, he added, baseline precautions such as basic personal hygiene, safe distancing and the wearing of face masks will continue to be a must throughout the three phases.

Mr Gan urged Singaporeans not to let up in the fight against Covid-19.

"We hope everyone will cooperate with us to support our plan and work together with us, so that we can safely remove the circuit breaker, safely open our economy and society," he said.

"And at the same time, make a safe transition towards a safe nation."