World No.1 Novak Djokovic says there is “no real proof” of match-fixing among top players as tennis authorities hosed down claims of evidence suppression after an incendiary media report into corruption in tennis.

A joint BBC-BuzzFeed investigation says current and past top-50 players, including several at this month’s Australian Open, are suspected match-fixers.

The report says a strong body of evidence was behind a referral of a core group of 16 men – including grand slam winners – to the Tennis Integrity Unit (TIU) in 2008.

No players are named in the report, and none have faced sanction.

Djokovic, speaking after his first-round victory at the Australian Open, said the allegations were just that.

“I don’t think the shadow is cast over our sport,” he said.

“There’s no real proof or evidence yet of any active players … as long as it’s like that, it’s just speculation.

“We have to keep it that way.”

ATP president Chris Kermode dismissed suggestions the sport didn’t take match-fixing seriously.

“Tennis authorities absolutely reject any suggestion that evidence of match fixing has been suppressed for any reason or isn’t being thoroughly investigated,” he said.

“All of us here in tennis are absolutely committed to stamp out any form of corrupt conduct in our sport.

“There is a zero tolerance policy on this. We are not complacent. We are very vigilant.”

BuzzFeed journalist Heidi Blake defended her report on ABC radio, saying tennis authorities had to be more transparent.

“In secret, behind closed doors, (tennis authorities) looked at the files … files full of evidence investigators themselves said was the strongest evidence they’d ever had,” she said.

“These are experienced betting, corruption and crime investigators.

“Tennis authorities looked at it and they decided not to investigate it further.

“I do think world tennis has some really serious questions to answer about why this evidence was under lock and key for so long.”

Player council vice president and world No.15 Gilles Simon savaged the report and the timing of its release.

“It’s useless … just dropping a bomb to (get people to) talk about it, waiting for the first day of a slam,” he said.

“If anyone has any evidence, say it, and we’ll be happy to know and take action.

“There is not much to say because there was not much inside.”

Kermode told the BBC match-fixing in tennis was at an “incredibly small level” but $14 million had been invested in the issue.

“I think it will be seen that tennis is in a very, very good place and we are acting accordingly,” he said.

TIU director Nigel Willerton said it would be inappropriate to disclose whether active players were the subject of current investigations.