The Tokyo Olympics are set to officially begin after a one-year delay, and the International Olympic Committee says organizers have done all they can to ensure a safe games as the coronavirus pandemic rages on.

“Everything that … can be done, everything that was recommended by all these experts — some of them here with us to deliver these games — we have done,” said Christophe Dubi, the IOC’s Olympic Games executive director.

He was responding to criticism that the organization was using “cheap measures” and had not listened to advice. Dubi told CNBC’s “Capital Connection” on Friday that the IOC received help from many experts around the world and “diligently followed up” on all the measures that were recommended.

“I think we’re doing just the right thing, and we do not consider at all that it is cheap,” he said.

World Health Organization Director-General Tedros Adhanom Ghebreyesus on Wednesday told organizers that they have done their best, and said the goal is not to have zero Covid cases during the games.

“The mark of success is making sure that any cases are identified, isolated, traced and cared for as quickly as possible, and onward transmission is interrupted,” Tedros said.

Dubi of the IOC said that’s what the organizers have done over the past few days, and will continue to do.

Looking to the future, including the 2022 Winter Olympic Games in Beijing, he said the IOC has learned how to create safe conditions, but that the situation is “very fluid” and will keep evolving.

“We have to be prepared for the worst and we have to plan for the worst,” he said. He added that there are “no talks whatsoever” about a postponement.

Earlier this week, Toshiro Muto, chief of the Tokyo Olympics organizing committee, did not rule out canceling the event if Covid-19 cases spike.

But Kirsten Holmes, a professor who focuses on events and tourism at Curtin University, said it would be “very difficult” for the organizers to cancel the games.

She said the Tokyo Games will be more logistically difficult than normal games, and there will need to be flexibility. “But I think it’s very unlikely that … the whole games will be stopped,” she said.

“We could see individual competitions within that postponed or perhaps canceled, if all of the competitors are unable to take part,” she told CNBC’s “Street Signs Asia” on Friday.

With no spectators or international visitors, Holmes said the games will be all about the athletes, some of whom may only have one chance to compete at this level.

“For the organizing committee, it’s very difficult for them to not go ahead, and that’s why … we will see the event proceed over the next couple of weeks and of course the Paralympic Games next month as well,” she said.

Disclosure: CNBC parent NBCUniversal owns NBC Sports and NBC Olympics. NBC Olympics is the U.S. broadcast rights holder to all Summer and Winter Games through 2032.