Health workers in coronavirus-hit Indonesia will get a third booster jab using the Moderna vaccine, authorities said, after several fully inoculated medics died from Covid-19.

The Southeast Asian nation, battling its most serious outbreak to date driven by the Delta variant, has relied heavily on the Chinese-made Sinovac jab in its vaccine roll-out.

But out of 1,000 medical workers who have died of Covid-19, more than a dozen were fully inoculated, according to the country's medical association, raising fresh concerns about Sinovac.

Health Minister Budi Gunadi Sadikin said the government would give 1.47 million health workers an extra jab using the vaccine made by US biotech company Moderna.