Japan's minister in charge of COVID-19 vaccinations is seen as the most suitable candidate to become the next prime minister, while a female former internal affairs minister has secured backing for her bid for the top job, media reported on Sunday.

Prime Minister Yoshihide Suga announced on Friday that he was stepping down, throwing a spotlight on a ruling party leadership election due on Sept. 29, with the winner of that taking over as prime minister.

The Kyodo news agency said nearly a third of respondents to a telephone poll it conducted this weekend said the minister in charge of vaccinations, Taro Kono, was most suitable to succeed Suga as prime minister.