TOKYO, Sept 26 (Reuters) - The race to determine Japan"s next premier will likely go to a run-off as neither of the two main candidates look able to secure an outright majority in the first round of voting three days from now, public broadcaster NHK said on Sunday. Taro Kono, the minister in charge of Japan"s vaccine roll-out, has been viewed as the top contender to become the next head of the ruling Liberal Democratic Party (LDP). The leader of the party becomes prime minister because of the LDP"s majority in parliament"s lower house. read more But Kono faces competition from former foreign minister Fumio Kishida; Sanae Takaichi, a former internal affairs minister; and Seiko Noda, a former minister for gender equality. Kono and Kishida command the most support but neither will have enough votes on Wednesday to secure an outright majority, NHK said, citing its polling of party members. A total of 764 people will vote in the race, including 382 lawmakers and grassroots party members nationwide, NHK said. About 30% of the lawmakers support Kishida, NHK said, with Kono expected to garner the most support among local party members, particularly in big cities such as Tokyo and Osaka. Kono and Kishida were followed by Takaichi, according to NHK. A hardline conservative, she is one of two women in the race and has picked up the backing of former prime minister Shinzo Abe. Separately, a Kyodo News poll on Sunday showed Kono remained the top pick among rank-and-file LDP members, with 47.4% support, although that was down by 1.2 percentage points from a similar survey earlier this month. The four candidates wrapped up a series of debates on Sunday, with both Kono and Noda voicing support for legislation allowing gay marriage. The candidates also called for more support for education, with Takaichi saying she wanted to extend existing financial support for families to include children in secondary school.