A joint investigation by BuzzFeed News and the BBC claims to have found "evidence of widespread match-fixing by players at the upper level of world tennis".
The allegations, BuzzFeed explained, are based on a cache of leaked documents and "analysis of the betting activity on 26,000 matches and interviews across three continents with gambling and match-fixing experts, tennis officials, and players".
According to the reports, the sport's governing bodies have been "warned repeatedly about a core group of 16 players" but none have faced sanctions.
The allegations were first revealed last night, on the eve of one of the sport's major tournaments, the Australian Open, getting underway in Melbourne.
Novak Djokovic is the first high-profile player to speak publicly about the allegations at the Australian Open today, saying he was offered $200,000 to fix a match in Petersburg in 2007, a tournament he did not eventually attend.
Chris Kermode, chairman of world tennis body, the ATP, denied the claims at a press conference in Melbourne: “The TIU and the tennis authorities absolutely reject any suggestion that evidence of match fixing has been suppressed for any reason or isn't being thoroughly investigated.
"While the BBC and BuzzFeed reports mainly refer to events from about 10 years ago, we will investigate any new information”.
The original document claimed betting syndicates based in Russia and Italy controlled games, making hundreds of thousands of pounds off each fixed result.
With the match fixing claims drawing global attention, the Australian Open chose an unfortunate time to select an official betting partner in William Hill, a deal which has been condemned as an “unprecedented tie” that is "completely inappropriate" for the sport by Australian senator Nick Xenophon.