Taro Kono, minister in charge of COVID-19 vaccinations, said Tuesday that some municipalities are slow to report on their vaccine rollout and indicated the possibility that the government might suspend vaccine shipments to such municipalities.

The government has a system to track the number of people being vaccinated across the country and asks local governments to input information from vouchers older people bring to inoculation venues.

The government decides the number of doses of Pfizer Inc.'s vaccine shipped to each municipality partly based on how many shots were administered there.

While the government is asking for quick input of information to the system on a daily basis, municipalities often fail to report on the day and some do the input work all at once at the end of the week, making it difficult for the central government to compile numbers.

"We might have to think of skipping (vaccine shipments to such municipalities) once," Kono said at a news conference. "We can't let them just stockpile."