TOKYO (REUTERS, AFP) - Japanese badminton trailblazer Kento Momota is set to miss the Rio de Janeiro Olympics later this year after admitting to gambling at an illegal casino, the local media reported on Thursday.

The 21-year-old world No. 2, 63rd-ranked Kenichi Tago and other team-mates from their domestic Nippon Telegraph and Telephone East Corp sides said they wagered at the Tokyo casino, which had since closed after police raids, Kyodo News reported.

Momota became the first Japanese shuttler to win the Badminton World Federation Super Series Masters Final in December and also landed the Asian nation a first men's singles world championship medal when he claimed bronze in Jakarta last August.

He was also a key member of Japan's historic Thomas Cup-winning side in 2014.

Nippon Badminton Association secretary-general Kinji Zeniya told Kyodo it would "probably be impossible" for the former world junior champion and other players to compete at the Aug 5-21 Games if the allegations were proven.

They have a serious responsibility to society," he told local media. "We must deal with this case strictly."

Zeniya added: "I'm shocked by this. I would like to deeply apologise to all the Japanese people and fans of badminton. At this stage we cannot endorse these players (for Rio) and it looks as if there will be a harsh punishment."

The association said that Momota had pulled out of next week's Singapore Open over the furore, adding that the player was likely to know his fate in the coming days.

"Momota won't play in Singapore," chief spokesman Norio Noto told AFP.

"At this stage we do not have all the facts but the executive board will meet to deliberate on his case. Once it does, it shouldn't take that long to come to a decision."

According to Japan's Sankei newspaper, an unidentified casino official claimed Momota and Tago - who won a record sixth national title in 2013 but was axed from the Japanese team last year for disciplinary breaches - "frequently" visited the parlour.

Gambling is largely illegal in Japan and the incident comes after a betting scandal that sent shockwaves through the country's most popular sport, baseball, just as it is bidding for inclusion in the 2020 Tokyo Olympics.

People found guilty of gambling in Japan can face jail terms of up to five years. Publicly operated gambling such as horse racing and "keirin" bicycle racing, however, is not illegal.