Tokyo — The man who was the musical brains behind a supposedly deaf composer dubbed "Japan's Beethoven" claimed on Thursday that the mock maestro was not hearing-impaired -- and couldn't even write sheet music.

The startling allegations come a day after composer Mamoru Samuragochi, 50, confessed to hiring another man to write his best-known works, as he shot to fame in the mid-1990s with classical compositions that provided the soundtrack to video games including Resident Evil.

Samuragochi has not responded publicly to the fresh allegations.

In an interview with weekly magazine Shukan Bunshun published Thursday, ghost composer Takashi Niigaki painted the picture of a carefully orchestrated fraud which saw Samuragochi -- who once called his hearing loss a "gift from God" -- play the role of tormented artist.

Niigaki, who said he became fed up with the fictitious story of a "digital-age Beethoven", said the composer would frequently slip out of his deaf persona.

"He may use some hand signs or read lips at the beginning, but he starts carrying on normal conversations as the discussion gets going," the part-time Tokyo music school teacher was quoted as saying.

"I think he had tough time pretending to be completely deaf. Recently, when I met him alone at his home, we talked normally from the start."

Niigaki added in a press conference broadcast live on Thursday that "from the day I first met him until now, I never once felt that he was deaf".

The ghost writer claimed he thought initially he was being hired as the composer's assistant.

"But later I found out that he cannot even write musical scores," he said, adding that "in the end, I was an accomplice".

The 43-year-old said he came forward after learning that Winter Olympics medal hopeful, figure skater Daisuke Takahashi, chose one of the composer's works for his programme in Sochi.

"I was afraid such a precious opportunity as the Olympics would be used to enforce the fiction that Samuragochi had constructed over years," he told the magazine.

Before his confession Wednesday, the composer said he went completely deaf about 15 years ago, but continued to work -- notably producing "Symphony No.1, Hiroshima", a tribute to those killed in the 1945 atomic bombing of the city.

The work became an extraordinary hit for a classical music CD, selling 180,000 copies in a genre where a hit often only logs 3,000 sales, according to its distributor.

The composer's reputation grew when broadcaster NHK aired a documentary in March last year entitled "Melody of the Soul", in which it showed him touring the tsunami-battered Tohoku region to meet survivors and those who lost relatives in the 2011 catastrophe.