A brash mayor of Nagoya city in Japan has triggered an outrage by suddenly biting the Olympic gold medal won by a Japanese women's softball team player when she met him as part of a celebratory function.

A report in Japan’s leading newspaper Nikkei Asia, the image of Kawamura's medal-biting went viral on social media, sparking a backlash against him not only from the athlete’s supporters and fans but also from other top Olympic athletes.

The act which was described as "lacking respect" for the athlete who won the medal and inappropriate amid the coronavirus pandemic.

Nagoya Mayor Takashi Kawamura misbehaviour occurred when Miu Goto, a 20-year-old pitcher hailing from the city, visited the municipal government following the team's victory over the United States at the Tokyo Olympics.

When 20-year-old Miu Goto put her gold medal around the neck of Nagoya Mayor Takashi Kawamura,  the 72-year-old first grabbed it and said, "It's heavy," before taking off his mask and suddenly biting it without taking her permission, the Nikkei report said.

"I myself have been careful not to scratch my gold medal," Judoka Naohisa Takato, who won gold at the Tokyo Olympics, said on Twitter. "Goto has too big a heart. I would've cried."

Yuki Ota, Japan's first Olympic fencing medalist, said Kawamura “lacks respect for the athletes who had to put their medals around their own necks or ask their teammates to do so as part of anti-infection measures. And now he bites the medal? It's inconceivable to me."

Toyota Motor Corp., which owns the club team Goto plays for, has also criticized Kawamura, saying in a statement, "It was an unworthy act and lacked respect" for the athlete's long-running efforts that helped the national softball team clinch victory.

Some older Olympians questioned whether athletes need to meet the mayor of their hometown to report on their achievements.

The Nagoya city office was flooded with over 4,000 complaints, forcing Kawamura to apologize.

"I saw the gold medal that I had admired and acted on impulse," Kawamura told reporters. "I made the symbol of years and years of hard work dirty. I apologize from the bottom of my heart."

The mayor also spoke with Yasuhiro Yamashita, president of the Japanese Olympic Committee, over the phone on Thursday to say sorry and also sent a letter of apology to Toyota.