Hashimoto accepted Sasaki's resignation after he proposed comedian and plus-size fashion icon Naomi Watanabe dress up as a pig for a section of the Olympic Games Opening Ceremony.

Sasaki said Watanabe, one of Japan's most famous comedians and entertainers, could perform at the Ceremony as an "Olympig" by coming down from the sky dressed as a pig.

The 66-year-old's suggestion, reported by the Japanese weekly magazine Shukan Bunshun, marked the latest controversy for organisers of the postponed Olympics and Paralympics after Organising Committee President Yoshirō Mori resigned last month following demeaning comments he made about women.

Hashimoto, appointed to succeed Mori, criticised Sasaki for his remarks at a press conference today and admitted the International Olympic Committee (IOC) had been "concerned" by the article in the magazine.

The seven-time Olympian and Olympic speed skating bronze medallist said she had discussed the issue with IOC vice-president John Coates, who chairs the IOC's Coordination Commission for Tokyo 2020.

"I was shocked after seeing the headline of the article," Hashimoto said.

"The remarks were inappropriate and very regrettable.

"This kind of problem should have never happened.

"The IOC also received the (magazine) article and they were quite concerned."

The suggestion from Sasaki, a former official at Japanese marketing giants Dentsu, also drew criticism from the Japanese Government.

Japanese Deputy Chief Cabinet Secretary Naoki Okada said Sasaki's suggestion was "totally inappropriate".

Sasaki has apologised for the offence he caused and said he regretted the proposal.

"For Ms. Naomi Watanabe, my idea and comments are a big insult," he said.

"And it is unforgivable.

"I offer my deepest regrets and apologise from the depth of my heart to her, and those who may have been offended by this."

Hashimoto vowed to appoint Sasaki's replacement as soon as possible.

Sasaki was originally chosen to oversee the Paralympic Ceremonies, but was promoted in December after organisers suspended the initial seven-person planning team following the postponement of the Games.

He was responsible for the flag handover ceremony at the Rio 2016 Olympic Games, which featured then Japanese Prime Minister Shinzō Abe dressed as Super Mario. 

Sasaki's resignation deals another blow to an already troubled build-up to the Games, postponed to this year because of the coronavirus pandemic.

It appears Tokyo 2020 have been swifter to act compared with the Mori incident as the former Japanese Prime Minister remained in his post for over a week before he eventually resigned amid international furore at his remarks.

Mori sparked controversy after claiming Board meetings involving women often overrun because they talk too much.

Tokyo 2020 has since added 12 women to its Executive Board as part of plans to improve gender equality within the organisation.