The Japan Sumo Association said it was quizzing all wrestlers in the sport's two top divisions to find if they were involved in fixing the outcome of matches. It expected to put together an initial report on their findings by the end of the week.
Sports Minister Yoshiaki Takaki said he was deeply concerned by the scandal, in which more than a dozen wrestlers or coaches have been implicated.
Amid a public outcry, the sumo association has decided to cancel its next major tournament - the first time that has happened in 65 years - and forego a number of exhibition or charity events until the matter is resolved.
"Sumo is in a crisis," Takaki said after meeting association officials Tuesday. "We hope for a quick investigation into the nature of this incident."
The latest scandal surfaced last week, when police informed sumo officials they had found suspicious text messages on the mobile phones of several wrestlers. The phones had been confiscated in an investigation into another scandal that came to light last year involving wrestlers betting on baseball games, allegedly with gangsters acting as go-betweens.
The scandal has become a national embarrassment for Japan because sumo is generally seen as a symbol of Japanese culture, and not merely a sport. Unlike other sports, the sumo association has special status that affords it tax benefits, and its wrestlers appear in public clad in traditional robes and wear their hair in top-knots.
There were indications that not all wrestlers were being cooperative with the investigation.
Kyodo news service and Japan's public broadcaster NHK said that some wrestlers had broken or replaced their old phones, possibly to avoid having them checked for incriminating text messages.
One wrestler said his wife stepped on his and broke it, Kyodo reported.
Allegations of match-fixing have long shadowed sumo, but the association has staunchly denied them and none had ever been proven.