Japan will start COVID-19 vaccinations at workplaces and universities on June 21 to speed up the pace of the country's sluggish vaccine rollout, its top government spokesman said Tuesday.

Chief Cabinet Secretary Katsunobu Kato told reporters the starting date could be brought forward if the government believes there is a prospect of completing the ongoing vaccination of those age 65 or older ahead of the initial goal of the end of July.

The expansion in the number of vaccination sites is meant to "reduce the burden on local communities and accelerate the pace of inoculations," Kato said, adding that the two-dose vaccine developed by U.S. biotech firm Moderna Inc. will be used.