“We are not sure yet, but we may be well be forced to take a few steps back before we can take more steps forward,” Lee said in a speech on Sunday at a convention by his ruling party. “But despite all this, I’m confident we will find a way to living with the virus and safely resume all the things we love to do.”

Singapore has been easing border restrictions as part of a wider plan to take an endemic approach to the virus, similar to that of many other countries. Thailand will be added to Singapore's vaccinated trave lane programme from Dec 16. But with the emergence of the new variant, several governments are taking fresh cautionary measures.

Israel and the United Kingdom have already imposed new travel restrictions to curb the spread of omicron, and Europe has discovered cases of the new variant across the continent. Singapore will require travellers via land from Malaysia to take an antigen rapid test upon arrival when the vaccinated travel lane comes into effect on Monday, the government said in a statement Sunday.