Singapore will from next month stop paying coronavirus medical bills of those who are unvaccinated by choice, officials have said, as a fierce outbreak put the city-state's healthcare system under strain.

The tiny country is experiencing its worst COVID-19 wave since the start of the pandemic, reporting around 2,000-3,000 cases a day and a handful of deaths.

The government had always covered the medical bills of all Singaporeans and other residents in certain categories infected with the virus, except for those who tested positive soon after returning from overseas.

But from Dec. 8, authorities will begin charging COVID-19 patients who are unvaccinated by choice, the ministry of health said Monday.

"Unvaccinated persons make up a sizeable majority of those who require intensive inpatient care, and disproportionately contribute to the strain on our healthcare resources," the ministry said in a statement.

Those affected will still be able to use regular financing arrangements to cover the cost, such as private insurance.

Bills for those who are ineligible for vaccination — such as children under 12 or those with certain medical conditions — will still be fully paid.

Singapore has one of the world's highest vaccination rates, with 85% of its 5.5 million population fully inoculated.

It has had a mild outbreak by global standards, and only faced a substantial virus wave in recent months after being hit by the delta variant.