TOKYO: Tokyo Olympics organisers said there is no problem with their new logo after discussions arose about possible plagiarism, with internet commentators suggesting there was a resemblance to an overseas design.

The emblem, unveiled last week, had already received mixed reviews from the Japanese public and risks becoming the latest in a series of missteps to mar Japan's reputation as it prepares to host the Summer Games for the second time in 2020.

Designed by Kenjiro Sano, the logo -- 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 motif 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 insisted the design underwent thorough checks before being unveiled.

"Prior to the selection of this design, the Tokyo 2020 Organising Committee conducted long, extensive and international verifications through a transparent process," they said in a statement.

The logo, which replaced a ring of Japanese cherry blossoms in rainbow colours used as a bid emblem, was unveiled on July 24 in a glitzy ceremony embellished by 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?"

IOC Director of Communications Mark Adams told NHK that similar problems had arisen before, most recently with the logo for the 2016 Rio Games.

Japan won the bid to host the Games in 2013 largely on its reputation for organisational prowess, but has been hit by a series of logistical problems ever since, including the scrapping of the design for the centrepiece Olympic stadium earlier this month due to soaring costs.