Chief Cabinet Secretary Katsunobu Katō made the claim in a meeting at Government headquarters yesterday.

"As a result of proper preparation and operation of the response system during the period [of the Games], no cyber-attacks were confirmed that could affect the operation of our systems," Katō said, according to Japanese public broadcaster NHK.

Prior to the Games, the usernames and passwords of ticket-holders and event volunteers were leaked online, but a Japanese Government official said the data breach was "not large".

In April 2020, a hacking incident impacted the Japanese Olympic Committee, forcing it to replace approximately 60 computers and servers that were infected with ransomware viruses.

These replacements cost a reported JPY30 million (£199,000/$269,000/230,000).

The Japanese Government, along with the Tokyo 2020 Organising Committee, conducted security exercises to simulate potential cyber-attacks before the Games.

Organisers also trained 220 so-called "ethical hackers" in a security scheme developed by the National Institute of Information and Communications Technology.

The Tokyo 2020 Olympics took place from July 23 to August 8 and were followed by the Paralympics from August 24 to September 5, after both events were delayed by a year because of the coronavrius crisis.

Last October, six Russian intelligence officers were charged in the United States for an alleged global computer-hacking operation that included the 2018 Winter Olympic Games in Pyeongchang.