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, Cummins 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.
Australian captain Pat Cummins insists he had no knowledge sandpaper was being used during the infamous 2018 Test series in South Africa.
In an impassioned press conference tackling Usman Khawaja's claims that every player in the team knew that ball tampering was taking place , Cummins said the allegations were "complete and utter nonsense".
"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 reporters in Sydney.
"I've said that consistently for the last eight years. I did not know that was happening.
Pat Cummins has refuted Usman Khawaja's claims that everyone knew about ball tampering in 2018. ( Getty Images: Darrian Traynor )
"But I think 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.
Pat Cummins says Usman Khawaja has been "casual" with people's lives. ( AAP: Dan Himbrechts )
In a press conference that lasted more than hour , Cummins said Khawaja had been "casual" with people's lives and reputations and said he never wanted to discuss the issue again.
"I was genuinely shocked this week when I found out that Usman admitted that he told Cam [Bancroft] to be careful when using sandpaper," he said.
"That's not the Usman that I know. It's not the Usman that I think has been part of a team that's helped rebuild the Australian cricket culture over the last eight years.
"And the one that would have stopped that from happening there and then.
"Usman's a friend, but friends aren't casual with each other's lives and reputations. In his book, Uzzy's been casual with my life and the lives of many others, and I think Australian cricket."
Cummins said he "100 per cent" supported the retired opener's right to tell his story.
"I'm really glad that he feels like he can," Cummins said. "But we have to be accountable for the things that we say and do."
