TOKYO: Japan's ruling party votes for a new leader on Wednesday who will almost certainly become the next prime minister ahead of a general election due in weeks and with the economy staggering from the COVID-19 pandemic.

Running for the top post are popular vaccine minister Taro Kono, 58, a U.S.-educated former defence and foreign minister seen as a maverick; ex-foreign minister Fumio Kishida, 64, a consensus-builder saddled with a bland image; former internal affairs minister Sanae Takaichi, 60, an ultra-conservative; and Seiko Noda, 61, from the party's dwindling liberal wing.

Party lawmakers will begin voting at 1:00 p.m. Japan time(0400 GMT) at a Tokyo hotel. Results from ballots of rank-and-file members and lawmakers are scheduled to be announced at 2:20 p.m.

If any candidate gets a clear majority, though projections show it is unlikely, that person will become the winner.

If not, the top two candidates in the first round will immediately go into a run-off vote. The results of the second round of voting are expected around 3:40 p.m.

Prime Minister Yoshihide Suga, his support in tatters ahead of the election, in a surprise move said he would step down after only a year as the Liberal Democratic Party (LDP) leader at a scheduled Sept. 29 party vote.

The new party chief is expected to become the next prime minister as the LDP holds a majority in the parliament's powerful lower house, but the contest has created political uncertainty in Japan with four candidates.

Last year, LDP factions rallied around Suga after Prime Minister Shinzo Abe quit following his nearly eight-year tenure, citing ill-health. But Suga's ratings tanked over his handling of the pandemic, prompting him to announce his departure ahead of a general election that must be held by Nov. 28.

This time, the race to become the country's next leader is too close to call.

Kono has the highest numbers in public polls, but Kishida leads among lawmakers, predictions show, as senior party bosses see him more stable.

Contenders need to attract votes from grassroots LDP members and rookie lawmakers, who have emerged as a force in the brief campaign preceding the vote and who are more likely to be swayed by popularity ratings, while also wooing LDP party bosses.

But rank-and-file members will have less say in the run-off, as the second-round vote gives greater weight to parliamentarians.

That change in the voting dynamics gives Kishida an advantage in the run-off battle against Kono. In case of the run-off, Takaichi, a contender in third, has agreed to support Kishida, Sankei Newspaper reported on Wednesday.

A win by Kono or Kishida is unlikely to trigger a huge shift in policies as Japan seeks to cope with an assertive China and revive an economy hit by the pandemic, but Kono's push for renewable energy and to remove bureaucratic obstacles to reform have made him appealing to investors and business chiefs.

Takaichi has been more outspoken on hotbutton issues such as acquiring the ability to strike enemy missile launchers. She has also made clear that as premier, she would visit the Yasukuni Shrine for war dead, seen in Beijing and Seoul as a symbol of Japan's past militarism. Kono has said he would not.

The candidates have also clashed over cultural values, with Kono favouring legal changes to allow same-sex marriage and separate surnames for married couples, both anathema to conservatives like Takaichi.

Kono and Kishida have pointed to the failure of Abe's signature "Abenomics" mix of expansionary fiscal and monetary policies and growth strategy to benefit households but offered few specifics as to how to fix the flaw, while Takaichi has modelled her "Sanaenomics" on her mentor Abe's plans.

For some time, the next prime minister will continue with expansionary economic policy, as the pandemic has yet to be contained, said Ryutaro Kono, chief Japan economist at BNP Paribas.

"Regardless of who becomes Japan’s next prime minister, the current expansionary fiscal and monetary policies will continue for at least another year because of the pandemic," he said.