Seen among the favourites in the race, Takaichi will be up against popular agriculture minister Shinjiro Koizumi, who is expected to formally declare Friday that he will stand.

Both are aiming to succeed moderate Prime Minister Shigeru Ishiba as the head of the ruling Liberal Democratic Party in a party vote slated for October 4.

"What we need now is politics that transforms people's daily lives and anxieties about the future into hopes and dreams," Takaichi said in a brief media address Thursday, announcing her candidacy.

"And it is also strong politics that will overcome the crisis Japan faces," she said.

Takaichi, 64, is a staunchly hawkish leader who has advocated for a conservative social agenda and robust national defence programmes.

On the economic front, she has pushed big government spending and low interest rates that echo policies of her political mentor late former prime minister Shinzo Abe.

She was also a regular visitor to the Yasukuni Shrine, which honours Japan's war dead including war criminals and is seen by Asian nations as a symbol of Japan's militarist past.

On China, she has been vocal on Beijing's military build-up in the Asia-Pacific region.

Takaichi has ran in past LDP leadership elections several times, and came in second last year to lose against Ishiba.

Other than Takaichi, three men have already formally declared their candidacy in the upcoming party vote, including Chief Cabinet Secretary Yoshimasa Hayashi, a soft-speaking political moderate known for his policy knowledge.

But Takaichi's biggest political rival is Koizumi, 44, a telegenic son of former Prime Minister Junichiro Koizumi, who also goes often to Yasukuni.

News agency Jiji Press's opinion polls released Thursday showed that Koizumi was the public's top candidate for the premiership, with Takaichi running a close second.

The leader of the ruling party can become the prime minister if they receive enough support from opposition parties to form a legislative majority, which is needed to take the top political seat.

The LDP decided to hold the election after Ishiba announced earlier this month that he would step down after losing two national elections in the past year.