The Sagamihara Municipal Government announced that it had been hit by landslides along National Highway 413 in Kanagawa Prefecture.

The landslides were triggered by the devastating rain caused by Typhoon Hagibis earlier this month. 

City officials warned that it could take several months to repair the damage. 

"We'll have a consultation with the [Tokyo] Organising Committee for the 2020 Games," a Sagamihara official told Japanese news agency JiJi Press. 

Large landslides struck at eight points along the highway in Midori Ward after the 19th named storm of the year dumped over 70 centimetres of rain in the area.

The Olympic road race is to be held on July 25 for men and on the following day for women. 

About 30 kilometres of the Olympic road race course is due to run through Sagamihara.

The course is set to start at a park in western Tokyo and finishes in Oyama, Shizuoka Prefecture, after going through Kanagawa and Yamanashi prefectures.

The men's 234km road race is due to climb the lower slopes of Mount Fuji.

The women's 137km race controversially does not include Japan's highest mountain.

On unveiling the routes in October 2018, Tokyo 2020 chief executive Toshirō Mutō commented: "The Olympic and Paralympic cycling courses will be quite challenging, traversing rugged up-and-down terrain near Mount Fuji. 

"The spectacle of the world's top athletes battling it out on these courses is bound to excite audiences."

Tokyo 2020 and the International Cycling Union both ignored a request from insidethegames for comment.