Sri Lanka's health authorities said on Wednesday that those who were yet to receive a booster dose of the COVID-19 vaccine should receive China's Sinopharm vaccines as coronavirus infections were likely to rise in the island country this year.

Chief Epidemiologist of the Health Ministry's Epidemiology Unit Samitha Ginige told reporters that 6 million people out of those above the age of 18 in Sri Lanka have not received their booster dose as yet.

"We have 1.8 million Sinopharm vaccines in stock," Ginige said.

He said there was no imminent threat to Sri Lanka despite a slight increase in COVID-19 infections globally.

"We cannot prevent any COVID-19 variant from entering the country. We can only delay it," he said, adding that the only way is to receive the COVID-19 vaccine.