England bowler Stuart Broad has admitted that he is baffled by Australia's decision to commit premeditated ball-tampering during the recent second Test against South Africa in Cape Town.

Captain Steve Smith and Cameron Bancroft confessed to cheating in a bid to gain an advantage in the Test, with Bancroft applying tape to the ball before hiding the evidence of his actions in his trousers.

However, the incident was caught on camera and Broad cannot understand why Australia would have tried to cheat having only recently thrashed England 4-0 in The Ashes.

"I saw Steve Smith in his press conference say it's the first time they've tried it - which to me, it's surprising why they'd change a method that's been working," Broad is quoted as saying by the Daily Mail.

"Look at the Ashes series we've just played, all those Test matches, and they've reverse-swung the ball sometimes in conditions you wouldn't expect it to.

"There was no evidence that they were doing this in the Ashes series, from what I've seen."

Smith and vice-captain David Warner have stepped down from their roles as a result of the controversy.