South African skipper Faf du Plessis said that Australia’s ball tampering row  during the third day of the third Test at Newlands is "much more serious" than the actions that saw the South Africa captain reprimanded two years ago.

Du Plessis was fined for applying saliva to the ball with a mint in his mouth during South Africa's second Test in Australia in 2016, but the batsman said his offence was not as bad as the tourists' antics in Cape Town.

Australian opener Cameron Bancroft admitted to trying to change the condition of the ball using tape after he was caught on camera doing so and then attempting to hide the tape in his trousers, as the umpires inquired.

Australia captain Steve Smith revealed that the tourists' "leadership group" had came up with a plan to change the condition of the ball during the lunch break in a desperate attempt to get back into the match, which was slipping away from them.

South Africa won the Test by 322 runs, as Warner and Smith stood down from leadership roles.

"For me, yes," Du Plessis said when asked if Australia's offence was worse.

Du Plessis continued, "Ball shining versus ball tampering are two very different situations and one is much more serious than the other. It's so difficult to say which is right and which is wrong. I think he [Smith] is trying to take responsibility, so there is right in that. But there is also right in people being responsible for their own actions."