Cummins hits out at Khawaja in passionate hour-long press conference - ABC News & Headlines – Australian Broadcasting Corporation

Pat Cummins said Usman Khawaja's claims that everyone knew about ball tampering in 2018 were "complete and utter nonsense".

In a press conference that lasted more than an hour, the Test skipper said Khawaja had been "casual" with people's lives and reputations.

Cummins also said he had seen ball tampering in Sheffield Shield, but would not elaborate on who or which team.

Pat Cummins has labelled Usman Khawaja's ball-tampering allegations "utter nonsense", revealing he has received legal advice that the claims are "probably defamatory".

In an extraordinary 70-minute press conference on Friday, Australia's Test captain ruled out legal action against his former teammate, but was scathing in response to the bombshell revelations in Khawaja's book.

Cummins repeated he and the bowlers' stance that he had no prior knowledge of plans for illegal ball tampering, until Cameron Bancroft was caught with sandpaper during a Cape Town Test match in 2018.

He agreed the bans handed down to Bancroft, David Warner and Steve Smith were too harsh after an investigation found they were the only players behind the plot, but rejected Khawaja's assertion that the entire team knew.

"When he says we all knew, if by that he means that we knew sandpaper was going out in the field, he's 100 per cent wrong," Cummins told a packed press conference in Sydney.

"I've said that consistently for the last eight years. I did not know that was happening.

Pat Cummins has rejected Usman Khawaja's claims that everyone knew about ball tampering in 2018. (Getty Images: Darrian Traynor)

"But Usman actually says things that are actually far more serious than that. He says that I and others were architects of a scheme to ball tamper with sandpaper.

Cummins said he did not remember any conversations around the team taking collective responsibility, as Khawaja said in his book he had pushed for.

The 33-year-old said he had exchanged some messages with Khawaja over recent days and planned to speak to him at some point.

Pat Cummins says Usman Khawaja has been "casual" with people's lives. (AAP: Dan Himbrechts)

But the pair's relationship is now considerably rocky.

"Usman's a friend, but friends aren't casual with each other's lives and reputations," Cummins said.

"In his book, Uzzy's been casual with my life and the lives of many others, and I think Australian cricket.

"I support his right to tell a story. I'm really glad that he feels like he can. But we have to be accountable for the things that we say and do."

Cummins said it was up to Cricket Australia whether they would reopen the investigation into the matter, something the organisation has already ruled out.

But he made it clear he wanted to move on from the scandal, declaring his willingness to take every question on Friday should make it the last time he has to speak about it.

"I did get advised this week that some of the things that were said are probably defamatory," Cummins said.

"But I won't be doing that. Like, you've got to move on. It's been eight years.

"We're moving on. You've got to draw a line at some point."

Now the Australia Test captain, Cummins pointed out that at the time of the scandal in South Africa, he was a 24-year-old just 13 Tests into his career.

Cummins said he had also not yet spoken to Warner since his backing of Khawaja's claims, and could not explain why their position was so different to his.

"That sounds like a pretty good question for those two," he said.

"Again, there's quite a few different accounts here, so they've got two accounts.

"There's 11 players in that room, so that means there's nine other guys who I think it's appropriate you give an equal amount of weight into their story as well."