Tokyo Governor Yuriko Koike has expressed shock and dismay over the decision to move the Olympic marathon and race-walking to northern Japan. (Photo: AFP)

The International Olympic Committee on Friday defended a plan to move the 2020 marathon and race-walking events from Tokyo to northern Japan, saying the decision was final, despite opposition from local officials.

John Coates, chairman of the IOC's Coordination Commission, said the decision was made after the world championships in Doha, which saw dozens of athletes receive medical attention in hot and humid conditions.

Coates met Friday with Tokyo's Governor Yuriko Koike, who earlier in the day said she was opposed to the plan to move the events to the city of Sapporo and described it as a "bolt from the blue".

Coates, speaking to reporters before talks with Koike, said the IOC had the "health and welfare of the athletes" in mind.

"The IOC was shocked by what we saw in Doha in very similar conditions in terms of temperature and humidity to what's expected here in Tokyo," he said.

"We didn't want Tokyo to be remembered for similar images as you will have seen in Doha in the marathon and in the race-walking events," he added.

Coates said other options that have been mooted, including starting the events as early as 3am, were impractical because of transportation issues and the difficulty of filming in the dark.

He said he recognised the "great disappointment" of people in Tokyo, but said the decision was final, even if city officials insist they still want to host the events.

"It's not a matter of if the Tokyo government insists, the decision has been taken," he said, answering "no" when asked if there was any chance the events could still be staged in Tokyo.

He said the IOC would propose holding the medal ceremonies for the events in Tokyo, as well as a parade through the city's streets featuring athletes.

There would also be discussions about the economic losses incurred as a result of the decision, he added.

'Very surprised' 

Koike repeated that she had been "very surprised" by the decision.

"Unfortunately we haven't been given a reason that's convincing to everyone," she told reporters.

Worries about Tokyo's notoriously hot and humid summer weather have dogged preparations for the Games, with the organisers investing significantly in measures including a special heat-mitigating coating on the roads being used for the marathon.

But the IOC announced earlier this month it wanted to move the marathons and race-walking events north, a proposal apparently decided without consulting either Tokyo or Sapporo officials, who expressed surprise.

Earlier Friday, Koike told Japan's Fuji TV she "didn't agree with (moving events to) Sapporo" and said the local government was still considering counter-proposals.

"There are voices among Tokyo residents who want explanations as to why this situation is occurring, and if a word from on high simply decides everything," she said.