SINGAPORE, Dec 14 (Reuters) - Singapore is considering requiring its residents to get a booster shot to qualify as fully vaccinated against COVID-19, its health minister said on Tuesday, as it seeks to protect its population from the Omicron variant. The city-state of 5.5 million people currently allows only those counted as fully vaccinated - or recipients of two shots - to enter malls or dine in at restaurants or at hawker stalls. From Jan. 1 it will bar unvaccinated employees from entering workplaces, unless they undergo tests each time. So far, 87% of Singapore residents have received at least two shots and 31% have had a booster. The Omicron variant, reported in more than 60 countries, poses a "very high" global risk, with some evidence that it evades vaccine protection, but clinical data on its severity is limited, according to the World Health Organization. read more "This is a clear signal that we all need to take our boosters, because with waning protection, full vaccination status cannot last perpetually," Health Minister Ong Ye Kung said during a media briefing, announcing the booster plans. Singapore reported 339 new coronavirus cases on Monday, the fewest since early September. It has so far recorded 16 Omicron variant cases, all but two of which were imported. The health ministry said it will allow up to 50% of workers, currently working from home, to return to their offices from Jan. 1.