Tokyo Olympics chief Yoshiro Mori bowed to mounting pressure and resigned Friday over sexist remarks, leaving a leadership vacuum after opposition emerged to his favoured successor.

The controversy over Mori's comments has been an unwanted additional headache for organisers already struggling to win over a sceptical public less than six months before the Games open.

After a two-hour meeting, Tokyo 2020 organisers said they will form a committee with a 50-50 gender mix to select Mori's replacement.

It will be headed by Canon CEO Fujio Mitarai, 85, an appointment that may not appease critics who say key positions consistently go to an entrenched old boy network.

Mori, 83, claimed last week that women speak too much in meetings, prompting outrage from officials, sports stars and Olympic sponsors.

On Friday he announced he would step down, effective immediately.

"My inappropriate statement has caused a lot of chaos. I would like to express my sincere apologies," he told Tokyo 2020's executive board and council.

"What is important is to hold the Olympics. It must not be the case that my presence becomes an obstacle to that."

Mori has sparked a firestorm of criticism after claiming women speak too much in meetings
Mori has sparked a firestorm of criticism after claiming women speak too much in meetings AFP / Philip FONG

Reports initially suggested Mori had selected well-known sports administrator Saburo Kawabuchi, 84, to replace him.

The transition appeared a done deal, with the former footballer describing his planned priorities in the new job to Japanese media.

But opposition to the selection of another octogenarian -- and Mori's control over the process -- quickly mounted.

By Friday afternoon, reports said Tokyo 2020 was under pressure to reverse the appointment, and Kawabuchi subsequently turned down the job.

Tokyo 2020's CEO Toshiro Muto said the new president should be chosen "as soon as possible" but set no deadline.

He said Mori's successor needed to have some Games experience, but that gender would not be decisive.

Mori is expected to be succeeded by Saburo Kawabuchi, a former footballer and long-time sports administrator
Mori is expected to be succeeded by Saburo Kawabuchi, a former footballer and long-time sports administrator AFP / YOSHIKAZU TSUNO

"I don't think we need to discuss the gender of the person. We will choose the most qualified person. Isn't that what we should strive for?"

Muto said organisers had also decided to form a team to promote gender equality and would seek to increase female representation among its staff and senior executives.

But he declined to be drawn on any deadline for improving female representation or any specific gender balance goal, saying he hoped to see progress by a March 22 board meeting.

Mori's resignation caps over a week of uproar after he told members of Japan's Olympic Committee that women have difficulty speaking concisely, "which is annoying."

He apologised but then defended his remarks and told reporters: "I don't speak to women much."

Several hundred Olympic volunteers have withdrawn in the wake of his comments and a petition calling for action against him gathered nearly 150,000 signatures.

On Friday Mori said he does not "look down on women", and had supported the seven women on the 35-member Tokyo 2020 board.

"They hesitated to raise their hand to speak up. I even called out their name to encourage them," he said.

As he stepped down, Mori was praised by officials including Tokyo Governor Yuriko Koike and the International Olympic Committee.

Mori had helped make Tokyo "the best-ever prepared Olympic city," IOC chief Thomas Bach said in a statement.

International Paralympic Committee president Andrew Parsons thanked Mori, adding that he hoped reaction to his comments would "be harnessed so that society places greater emphasis on diversity and inclusion."

The race to fill Mori's former post now appears wide open, with reports suggesting Olympic Minister Seiko Hashimoto -- a former Olympic athlete and one of just two women in Japan's cabinet -- is a leading candidate.

The fallout comes with organisers already battling public doubt about holding the international event this summer.

Around 80 percent of Japanese polled in recent surveys back either further postponement or outright cancellation.

Organisers have tried to quell the disquiet by releasing virus rulebooks, but doubts persist with Tokyo and other regions under a Covid-19 state of emergency.