Tokyo Olympics organisers said there is no problem with their new emblem after discussions arose about possible plagiarism, with internet commentators suggesting there was a resemblance to an overseas logo.
The emblem, unveiled last week, had already gotten mixed reviews from the Japanese public and risks becoming the latest in a series of missteps to mar Japan`s can-do reputation as it prepares to host the summer Games for the second time in 2020.
Designed by Kenjiro Sano, the emblem - which includes black for diversity and a red circle that echoes the Japanese flag - centres around a loose representation of the letter "T".
But questions about the design erupted on social media after Belgian-based designer Olivier Debie uploaded the logo for the Theatre de Liege in Belgium, with many commentators demanding clarification about what they said was too much similarity.
"Eh, going as far as plagiarism? We must have an explanation," one Japanese commenter tweeted.
NHK national television said the emblem also resembled the logo drawn up by a Spanish designer to help raise money for Japan after the March 11, 2011 earthquake and tsunami.
The Tokyo 2020 Organising Committee said the design underwent thorough checks before being unveiled.
"I have heard from the games organisers that before the emblem was announced, they did a search of trademarks both in Japan and overseas, so it is not a problem," chief cabinet secretary Yoshihide Suga told a news conference.
The emblem, which replaced a ring of Japanese cherry blossoms in rainbow colours used as a bid emblem, was unveiled on July 24 amidst strobe lights and billowing smoke in a Tokyo plaza as hundreds watched.
But the immediate response was mixed, with one man overheard saying, "Who decided on that thing?"
An IOC official told NHK similar problems had arisen before, most recently with the logo for the 2016 Rio Games.
Japan won the Olympics over Madrid and Istanbul in 2013 largely on its reputation for organisational prowess but has been hit by a series of problems that include scrapping the design for the centrepiece Olympic stadium, the New National Stadium, earlier this month due to soaring costs.