Mori, who has a reputation for public gaffes, verbally attacked those athletes on stage at a send-off event for the Japanese Olympic team after they sung the “Kimigayo” anthem.

“Why can’t you all sing the national anthem together?” he said.

The former Japanese Prime Minister, who once refused to speak English at a Sochi 2014 press conference because it was the “language of the enemy”, then went on to declare that those athletes who did not sing the anthem with gusto do not deserve to compete for Japan.

“It’s not just a case of mouthing the words,” Mori said.

“If you get to stand on the winners’ podium, sing the national anthem with a loud voice.

“If you won’t sing the national anthem, then you can’t consider yourselves representatives of Japan - that’s what I want to say to you.”

During the event, Mori pointed to Japan’s Rugby World Cup team, who earned global plaudits for their displays at last year’s tournament in England, as an example of athletes from the country singing the anthem passionately.

A number of the players in the team were visibly emotional when performing a rendition of “Kimigayo” at the competition.

Japan’s women’s football side were also in “floods of tears” during their country’s anthem at the 2011 World Cup, where they beat the United States on penalties in the final.

The development marked the latest in a series of embarrassing errors from Mori, who also publicly criticised Vancouver 2010 figure skating silver medallist Mao Asada at Sochi 2014.

After Asada, one of Japan’s most recognised sportswomen, had failed to complete a trademark triple axel, Mori declared: “That girl, she is always falling at critical moments.”

Around 10,000 people attended the send-off event, where Japan set a medal target of between 22 and 30 golds.

Japan claimed a record haul of 38 at London 2012, seven of which were gold.

“I really feel the onus is on me,” Yuji Takada, the delegation’s general manager, said.

“I want us to win as many medals as possible.”