Japanese education and sport minister Yoshiaki Takaki, who oversees the sumo industry, said the head of the Japan Sumo Association had informed his ministry that three wrestlers had confessed to fixing results, Jiji Press said.
The report came a day after sumo association chairman Hanaregoma issued an apology over claims that wrestlers had colluded, but stopped short of confirming the allegations.
Bout-rigging claims have long stalked the sport, which has its roots in Japan's native Shinto religion, but there has never previously been any confirmation.
Local media said on Feb 2 that police found messages indicating wrestlers were trading wins or fixing fights during an investigation last year into organised crime-linked gambling in sumo circles.
The messages were discovered on cellphones confiscated from several wrestlers during a probe into betting on baseball, media reports said.
The new allegations are the latest controversy to throw light on the cloistered world of a ritualistic male-only event in which contestants toss salt to purify the ring before fights.
That image has been tarnished with revelations of drug use, extortion and the 2007 death of a trainee who died during hazing.
Last year, scores of sumo wrestlers, who are expected to act as role models in Japan, admitted to betting illegally on baseball games in gambling organised by bookmakers linked to organised crime.