The city-state of 5.45 million people has been reporting record daily Covid-19 infections of more than 3000 over the past few days, though almost all the cases are asymptomatic or mild.
About 83 percent of the population is fully vaccinated, one of the world's highest rates.
Singapore recently reimposed coronavirus restrictions to buy time to prepare to live with the disease. But the step was met with rare frustration as the Government walks a fine line between reopening and preventing hospitals from being overwhelmed.
Prime Minister Lee Hsien Loong said Singapore will reach a new normal and can lighten restrictions when cases stabilise, even if they stay in the hundreds.
"It will take us at least three months, and perhaps as long as six months, to get there," Lee said in an address to the nation, which has largely kept the virus at bay since last year with masks, contact tracing and a closed border.
"After this surge stabilises, we may still see future surges, especially if new variants emerge.
"We may have to tap on the brakes again if cases again grow too fast to protect our healthcare system and healthcare workers."
The Government will tighten rules for those who remain unvaccinated from Wednesday, barring them from entering malls and eating at the country's ubiquitous hawker centres. It will review some Covid-19 curbs in a week or two.
Singapore's travel programme for fully vaccinated people began in September with Germany and Brunei, and will include South Korea from next month.
Up to 3000 travellers will be able to enter daily through the vaccinated travel lanes, a far cry from the record 19.1 million travellers to the city-state in 2019. Borders remain largely closed to key Asian countries.
Singapore is discussing two-way quarantine-free travel with several more countries, the Government said.
"We hope this further easing of measures and expansion of Singapore's border reopening will spur other markets to similarly navigate their pathways towards restarting air travel," said Philip Goh, Asia-Pacific vice-president for the International Air Transport Association.
Singapore Airlines said in a statement that it will expand its vaccinated travel lane networks to 14 cities.
The flagship carrier, which relies solely on international travel, lost a record $US3.15 billion in the year to March, its second year in the red.
Singapore's Changi Airport was among the world's busiest in 2019, with more than 68m passengers before travel crashed last year due to the pandemic.
"Since the Singapore economy is extremely dependent on external demand for our goods and services, very simply put, any moves that help to lift the number of flights handled by Changi Airport will add to our GDP," said Song Seng Wun, an economist at CIMB Private Banking.
The country has hit some hiccups on its transition to an endemic Covid-19 as the population was focussed on avoiding it for nearly two years. Its leader said the high vaccination coverage meant people will be better protected from the virus, which is likely to infect nearly everyone.
"Let us go about our daily activities as normally as possible, taking necessary precautions," Lee said. "We should respect Covid-19, but we must not be paralysed by fear."
- RNZ
