Health Minister Ong Ye Kung has said that the Government is monitoring hospital capacity closely, and may have to impose more restrictions if the Covid-19 situation worsens.
Singapore already has a suite of measures in place and to go further would be a "last resort", he added in Mandarin in an interview on Tuesday with Lianhe Zaobao that was published yesterday.
But the Delta variant has continued to spread quickly despite the measures in place, and daily cases have exceeded earlier projections.
There were 1,457 new Covid-19 cases yesterday, the highest ever daily record since the pandemic began, and the fourth time in five days the number has exceeded 1,000.
"We had planned to have a preparatory period, during which we can gradually open up while handling perhaps 100 to 200 cases a day. But Delta did not wait for us to be ready and attacked us first," said Mr Ong.
"The fight against Delta is really like a war... and it can spring surprises which you never expected, so you have to be able to adapt and change strategies quickly."
He added that two factors are crucial in deciding if Singapore has reached a critical stage - the number of serious cases and hospital capacity. The Government has been keeping a close watch on both indicators to ensure intensive care units and the healthcare system in general are not overwhelmed.
The number of patients in intensive care units was 19 yesterday, up from nine last Wednesday.
"If this does not work, then we will have to explain to people frankly about the need for tighter restrictions," said Mr Ong, one of three co-chairs of the multi-ministry task force overseeing the national response to Covid-19.
Asked about his assessment of the current situation, Mr Ong said that as at last week, things were still under control. But he added that the situation changes daily.
He also noted that a new balance had to be struck with the virus, and people would have to learn how to coexist with Covid-19.
At the current stage of the pandemic, it is no longer possible and also futile to go into protracted lockdowns, he said, noting that infection numbers will inevitably go up again once lockdowns are lifted.
Simultaneously, this does not mean Singapore should lift all restrictions and open up to the extent that countries like Britain and the United States had. "What we need to do is to take the middle road, and everyone needs to adjust so that we can co-exist with the virus and find a new balance," he said.
He added that there was a difference between co-existing with Covid-19 and treating it as an endemic disease like influenza.
There are too many unknowns with Covid-19, which is also more lethal, he said, citing Professor Leo Yee Sin, the executive director of the National Centre for Infectious Diseases, who had said it is too early to tell if it will become a disease like the flu.
The growing number of cases in recent days has sparked concern and anxiety, with some asking if the Health Ministry can provide information about the places where multiple people were infected.
Asked about this, Mr Ong said that his ministry will try its best to announce where the clusters are and to do so earlier in the day.
But he added that with most people vaccinated and not exhibiting symptoms when infected, it has become trickier to link cases and figure out how the virus is spreading.
Citing the outbreak at the Jurong Fishery Port, he said: "By the time it's discovered, the cases were already high, it's already too late. But if we find out early, we will definitely announce it as soon as possible, so people can be careful."
The minister also acknowledged that it was impossible for people to stay home all the time, but advised them to pay attention to personal hygiene when out, in particular the elderly. "Wear a mask, don't pull it down to talk to your friends. Try not to touch too many things and don't rub your eyes or pick your nose," he said. "Paying attention to these things will have a great effect in preventing infections."