The majority of the 38,000 competitors have been affected by the change with athletes from around the world unable to compete at the event on March 1. 

All registered runners for this year's event can be deferred for the 2021 marathon, but they will controversially have to pay the race fee again without a refund for this year. 

However, the elite races, the men's, women's, wheelchair men's and wheelchair women's, will still go ahead.

The race will count as part of the Japanese trials for the Olympic and Paralympic marathons.

Ethiopia's Birhanu Legese and Ruti Aga won last year's edition with Swiss wheelchair pair Marcel Hug and Manuela Schär also taking titles.

Japan's men's marathon record holder Suguru Osako is set to compete for the final spot on his country's men's team after narrowly missing qualification at the first Olympic trials in September.

On that day, Shogo Nakamura won by eight seconds ahead of Yuma Hattori, who also booked his place, with Osako missing out by just five seconds.

In the women's race, Honami Maeda and Ayuko Suzuki confirmed their spots while Rei Ohara, who missed Rio 2016 by one second and was four seconds off automatically qualifying this time around, will look to confirm her Tokyo 2020 place.

Japan has been at the centre of recent news regarding the disease after a cruise ship with sick passengers ported in Yokohama, with 454 on board having cases of the virus.

On land, 65 people have become confirmed patients, making the country the third-most affected behind China and Singapore.

More than 70,000 people have now been infected around the world with 1,776 deaths so far.