Japan's minister in charge of vaccines, Taro Kono, led a public opinion poll on who should succeed Prime Minister Yoshihide Suga as head of the ruling Liberal Democratic Party.
Kono had 27 per cent support in the poll by the Nikkei newspaper and TV Tokyo that asked who would be "the right person" to lead the party and become the next prime minister.
The results of the September 9-11 poll were released on Saturday.
Former LDP Secretary-General Shigeru Ishiba was next with 17 per cent, and ex-policy chief Fumio Kishida was third with 14 per cent. Former Interior Minister Sanae Takaichi was fifth with 7 per cent.
Kono, who also serves as minister of administrative reform, announced his candidacy on Friday, the third to make his intention official after Kishida and Takaichi.
Ishiba may not run for the party's leadership and instead will likely support another candidate, the Jiji news service said Saturday, citing sources close to him.
Suga, in a surprise move, said on September 3 he would step down, marking an end to a one-year tenure that was marred by plunging public support and dissatisfaction with his coronavirus response.
That set the stage for a September 29 leadership vote among grassroots LDP members and lawmakers. The winner is virtually assured the premiership because the LDP has a majority in parliament's lower house.
Following the LDP leadership vote, Japan will likely hold a general election in the first half of November, Kyodo reported citing ruling party lawmakers.
The Nikkei/TV Tokyo poll follows earlier ones showing strong public support for Kono, 58, to succeed Suga.