The Japanese government has insisted the Tokyo Olympics will go ahead this summer despite reports that the already postponed games will be cancelled amid growing concern about the level of Covid-19 infections.

Manabu Sakai, Japan’s deputy chief cabinet secretary, said he “completely denied” a report in the Times of London that the government had resigned itself to scrapping the games.

But officials at the Tokyo organising committee said they were concerned about negative domestic sentiment around the Olympics, with Japan’s borders closed and the capital under a state of emergency to battle a surging virus outbreak.

Organisers said the next crucial decision — on whether to allow spectators or refund their tickets — will have to be made in the coming months, but it would not affect whether the event goes ahead. “For us, there is no limitation or deadline until we start receiving the athletes,” said one Tokyo 2020 official.

However, diplomats in Tokyo said national Olympic committees around the world would need to make definitive financial commitments to attend the games by the end of March, creating a de facto deadline for the hosts.

“Looking at the situation abroad as well, then of course at some point we’ll have to make a judgment about whether the games can go ahead,” said Mr Sakai.

The 2020 Tokyo Olympics were postponed last March despite repeated assurances that the event would be held as planned.

The 2024 Olympics have already been awarded to Paris and 2028 to Los Angeles. Both the IOC and the Japanese government accept that Tokyo 2020 cannot be postponed again, so the next opportunity to host the games would be 2032.

A Tokyo-based adviser to two global sponsors said that if the International Olympic Committee wanted to cancel the games, it would most likely make a special request to the UN or the World Health Organization for formal advice.

If that advice supported a cancellation, the IOC would be insured on lost broadcast fees and Tokyo would not have to pay compensation. “Neither party will admit to wanting to cancel until that advice is given,” the person said.

A schedule of test events, some of which are also Olympics qualifiers, starts on March 4. The torch relay is due to begin in Fukushima on March 25.

Rather than forcing a cancellation, however, people close to the Tokyo organising committee said there could be alternative qualifying arrangements made if international athletes were unable to attend those events.

The Japanese government would have to ease border restrictions if it wants the games to proceed, but it fears a domestic backlash given fears about new Covid-19 variants circulating in the UK, South Africa and Brazil.

Tokyo organisers are planning for an Olympics without vaccinations, as they do not believe national immunisation campaigns will reach healthy young athletes by the summer.

Plans under discussion to manage the pandemic include a scheme that would station about 10,000 doctors and nurses around Olympic venues to provide medical assistance.

But Haruo Ozaki, head of the Tokyo Medical Association, warned in an interview with Japanese media that the steep rise in coronavirus cases had already placed a heavy strain on medical staffing. He called on the government to lay out a clear guide for how far — and by what specific date — case numbers would need to fall to justify the deployment of doctors and nurses to the games.

Dick Pound, an IOC official, told Kyodo News this week: “Nobody can guarantee (that the Olympics will go ahead as planned). But I think there's a very, very, good chance that they can, and that they will.”