Olympics chief Thomas Bach agreed that 2021 was the "last option" for holding the delayed Tokyo Games on Thursday, stressing that postponement cannot go on forever.

Bach said he backed Japan's stance that the Games will have to be canceled if the coronavirus pandemic isn't under control by next year.

In March, the Tokyo 2020 Olympics were postponed to July 23, 2021m over the coronavirus, which has killed hundreds of thousands of people around the world and halted international sports and travel.

"Quite frankly, I have some understanding for (Japan's position) because you cannot forever employ 3,000 or 5,000 people in an organizing committee," Bach, president of the International Olympic Committee (IOC), told the BBC.

"You cannot every year change the entire sports schedule worldwide for all the major federations," Bach said.

"You cannot have the athletes being in uncertainty, you cannot have so much overlapping with a future Olympic Games," he said.

The IOC leader said it was a "mammoth task" to reorganize the Olympics, which have never been canceled outside of the World Wars.

However, Japanese officials have been clear that they have no intention of postponing the Games again beyond next year.

Bach warned that "nobody knows" how the situation will play out, but said the IOC will act on advice from the World Health Organization (WHO).

"We have established one principle and this is to organize these Games in a safe environment for all the participants," he said.

"Nobody knows what the world will look like in one year and two months from today, so we have to rely on (the experts)," Bach said.

'No taboo'

Bach wouldn't say whether a vaccine was a prerequisite for going ahead with the Olympics but was lukewarm on the idea of holding them without fans.

"This is not what we want," he said. "Because the Olympic spirit is about also uniting the fans and this is what makes the Games so unique that they're in an Olympic stadium; all the fans from all over the world are together."

"But when it then would come to the decision ... I would ask you to give me some more time for consultation with the athletes, with the World Health Organization, with the Japanese partners," Bach said.

The IOC has already set aside $800 million to help organizers and sports federations meet the extra costs of a postponed Olympics.

According to the latest budget, the Games were due to cost $12.6 billion, shared between the organizing committee, the government of Japan and Tokyo city.

But Bach said there should be "no taboo" in cutting costs for next year's Games.

"They will definitely be different, and they have to be different," he said. "If we all have learned something during this crisis, (it is) to look to the essentials and not so much on the nice-to-have things."

"So this concentration on the essentials should be reflected in the organization of these Games ... there should be no taboo."

The loan program is being run with Switzerland’s federal government, which announced aid for Olympic sports federations based in the country. The IOC will put up half the money for those loans and federal and state authorities provide 25% each.

A detailed breakdown of how the remaining $650 million could be allocated will be formulated in the months ahead, IOC chief operating officer said.

The IOC had a revenue of $5.7 billion from the 2013-16 Olympic cycle. That figure would likely have approached $7 billion for the next four-year period tied to the Tokyo Games.

Before the postponement, Japanese organizers officially said the bill for the games would be $12.6 billion. However, a government audit in 2019 said it was at least twice that and mostly in taxpayer money.