Hours after International Olympic Committee president Thomas Bach had insisted cancelling the Games was "never an option", the head of the Tokyo Organising Committee refused to rule out doing just that if coronavirus cases continue to rise.

In a sign of the increasing schism between the two organisations, Toshiro Muto vowed to maintain discussions relating to the local virus rate, and added, in a question which invited him to remove the possibility of cancellation: "We will think about what we should do when the situation arises."

The Tokyo Games will be the first to take place under a city-wise State of Emergency. New daily cases have risen again to over 1,000, with more than 70 Games-related personnel testing positive since July 1, including three athletes in the Olympic Village.

Frustration has grown over inconsistent quarantine measures for close contacts of a positive case, with athletes allowed to train and compete after a single negative PCR test, while others, including the Japanese public, must endure 14 days in isolation.

Some members of the media who have been required to quarantine have found themselves sharing lifts and lobbies of supposedly sealed hotels with Japanese guests, whilst others have been able to subvert the three-day process seemingly at random.

Bach predictably sought to strike a different chord in his opening comments at the 138th IOC Session in Tokyo, insisting the Games could have "fallen to pieces" if the IOC had not taken the unprecedented decision to reschedule.

Bach said: "Cancellation would have been the easy way for us. We could have drawn on the insurance that we had at the time and moved on to Paris 2024.

"But in fact, cancellation was never an option for us – the IOC never abandons the athletes.

"Imagine for a moment what it would have meant if the leader of the Olympic movement, the IOC, would have added to the already many doubts surrounding the Olympic Games, it would have poured fuel on to this fire.

"Our doubts could have become a self-fulfilling prophecy. The Olympic Games could have fallen to pieces. That is why we had to keep these doubts to ourselves."

Bach undertook three days of quarantine upon his arrival in Tokyo two weeks ago, and subsequently received a lukewarm reception on a visit to Hiroshima.

Friday's opening ceremony will also take place behind closed doors and is expected to be a dramatically scaled-back affair, with only media and dignitaries present, but it has been confirmed that Japan's Emperor Naruhito will attend.