Philippine President Rodrigo Duterte threatened to jail people who refuse to be vaccinated against the coronavirus as the country battles one of Asia's worst outbreaks, with over 1.3 million cases and more than 23,000 deaths.

"You choose, vaccine or I will have you jailed," Duterte said in a televised address on Monday following reports of low turnouts at several vaccination sites in the capital, Manila.

Duterte's remarks contradict those of his health officials who have said that while people are urged to receive the COVID-19 vaccine, it was voluntary.