Of Cambodia's more than 16 million people, 10 million have been vaccinated against Covid-19 so far, one of the highest rates in Southeast Asia.

"We vaccinate people not only to save lives but to save the economy and society. Reopening of the economy and society is necessary," Prime Minister Hun Sen said at the launch of the program.

"We are willing to spend hundreds of millions of dollars on vaccines to vaccinate people in order to attract billions of dollars for the economy in return."

Cambodia has been using vaccines made by China's Sinovac and Sinopharm and the British-developed AstraZeneca vaccine on adults and has also been vaccinating children over 12. The health ministry said the Sinovac vaccine would be given to children aged 6 to 12.

Chile and the United Arab Emirates have also approved vaccinating younger children, while Cuba is administering shots masse to toddlers. In China, a government disease control expert on Thursday said the country should consider vaccinating children under 12.

In the United States, top health officials believe the vaccine developed by Pfizer and BioNTech could be authorized for children aged 5 to 11 next month.

Cambodia's tourism- and manufacturing-led economy contracted 3.1 percent last year and is forecast to grow 4 percent this year, the World Bank says.

The country has recorded more than 102,000 coronavirus cases and more than 2,000 deaths since the pandemic began, the vast majority this year.