British race walker Tom Bosworth criticised the conditions at the hotel in Sapporo, while there had been fears the temperature may not be as cool in the capital of Hokkaido Prefecture as had been hoped.

The IOC switched the venue for the race walks and marathons to Sapporo, more than 830 kilometres from Tokyo, because of concerns over the extreme heat in the Olympic and Paralympic host city.

Up until the last few days, there was hardly any difference in the forecast in Sapporo and Tokyo, although it is now expected the weather in the former will be around four degrees cooler than the capital when it stages the 20 kilometres race walk tomorrow.

Sapporo last month recorded its highest temperature for 21 years.

Bosworth, among the entrants for the 20 kilometres race tomorrow, described Sapporo as being "like a prison" and criticised the standard of food being served to athletes, which he called "cold slop".

"Any chance, in the week of our race, we could get some food?" he wrote on Twitter before deleting the posts when they started going viral. 

"Like meals? Not cold slop, steamed onions or partly cooked pasta? 

"This is the ‘pinnacle of sport.’ 

"Sapporo feels like a prison."

Both World Athletics and Tokyo 2020 were thought to have opposed the move to Sapporo and were caught by surprise by the IOC's decision.

Tokyo Governor Yuriko Koike, who described the venue switch as "a tremendous shock", had called for the events to remain in the capital before reluctantly agreeing to support it.

"I do not think we regret making every attempt to make the conditions for athletes as good as we can," IOC Presidential spokesperson Mark Adams said.

"Our information like everyone else that in general the average temperature is five degrees less in Sapporo than Tokyo.

"It was a brave and difficult move and we did it in collaboration with World Athletics and Tokyo 2020 - they all had to be in approval of that.

"I think you would agree that any attempt should be made to make the conditions for participation in the Games by athletes as comfortable as possible."

Ukrainian race walker Nazar Kovalenko has been ruled out of the events in Sapporo after the Court of Arbitration for Sport rejected his appeal to overturn his ban from the Games over missed doping tests.

Kovalenko had hoped to be cleared to race in the 20km.

Fans have been told to stay away from all of the events at Sapporo Odori Park because of COVID-19 countermeasures in place at the Games.

The men's 50km and women's 20km race walks are scheduled for Friday (August 6).

The women's marathon is due to follow on Saturday (August 7), when IOC President Thomas Bach is expected to be in attendance, before the men's marathon takes place on the final day of the Games on Sunday (August 8).

Sapporo has already staged matches in the men's and women's football tournaments at Tokyo 2020.