TOKYO: The Japanese designer of the Tokyo 2020 Olympic Games emblem hit by a controversy over its similarity to a Belgian design said on Friday he had never seen the other logo, after the Belgian designer hinted at legal action.

Questions about whether the Tokyo emblem was too close to the logo for Belgium's Theatre de Liege erupted on social media earlier this week after designer Olivier Debie drew attention to it, with many demanding an explanation.

Debie said on Thursday that he was astonished by the resemblance and that the form of the letters was almost identical. He and the theatre are consulting lawyers, he added.

"After seeing this, I have a hard time imagining that the graphic designers who worked on it have never seen my logo," he said.

Kenjiro Sano, who designed the Tokyo emblem - a loose representation of the letter "T" that includes a red circle mirroring the Japanese flag - countered by saying his goal had been to create a distinctively Japanese design.

"I had absolutely no previous knowledge of the design in question, and I certainly did not refer to it when creating my design," Sano said in a statement.

Kyodo news agency quoted Debie as saying he might ask for the Tokyo emblem to be withdrawn or changed. He also said that the theatre logo was not a registered trademark but that it had appeared in 2013.

Officials, including Olympics Minister Toshiaki Endo, reiterated that they had carried out exhaustive checks and research on international trademark protection before announcing the emblem.

The mark, which has had mixed reviews from the Japanese public, replaces a ring of cherry blossoms in rainbow colours used as an emblem during Tokyo's bid for the Games.