Japan's minister in charge of the Tokyo 2020 Olympics stepped down on Wednesday after the latest in a series of gaffes.

The resignation comes less than 500 days before Tokyo hosts the Games, and follows a decision by the head of Japan's Olympic Committee to step down as French authorities investigate him.

Japan's Olympic Minister Yoshitaka Sakurada attends a news conference at Prime Minister Shinzo Abe's official residence in Tokyo, Japan October 2, 2018. (File Photo: VCG)

Yoshitaka Sakurada "requested to resign after he hurt the feelings of victims" of the 2011 quake and tsunami, Prime Minister Shinzo Abe told reporters.

"And I accepted it," he said. "I deeply apologise for his remark to the people in the disaster-hit areas," Abe said, adding he accepted responsibility for appointing Sakurada as minister.

The resignation comes after Sakurada said at a gathering of a member of the ruling Liberal Democratic Party from the disaster-hit northern region that the lawmaker was more important than the recovery of the region, according to the public broadcaster NHK.

The March 2011 tsunami, triggered by a massive undersea quake, killed around 18,000 people and swamped the Fukushima nuclear plant, sending its reactors into meltdown and leading to the world's worst nuclear disaster since Chernobyl.

More than 50,000 people have not returned to their home towns.

Japan has dubbed the 2020 Games the "Reconstruction Olympics" and wants to showcase recovery in regions devastated by the disaster.

Sakurada had already come under fire for various gaffes such as commenting that he was very disappointed about teenage swimming star Rikako Ikee announcing her leukaemia diagnosis.