South Africa captain Faf du Plessis insisted Wednesday he wasn't a cheat and warned cricket authorities had opened a "can of worms" after he was found guilty of ball-tampering in controversial circumstances.

Du Plessis was fined his match fee on Tuesday after being caught on camera sucking a mint and rubbing saliva into the ball during last week's second Test against Australia in Hobart.

But du Plessis, who won backing from leading figures including Australian captain Steve Smith, said he didn't think he had done anything wrong.

"I still completely disagree with that (decision)," du Plessis told reporters in Adelaide. "I feel like I've done nothing wrong... it's not like I was trying to cheat or anything.

"For me (ball-tampering) is picking the ball, scratching the ball. Shining the ball, I think all cricketers would say, is not in the same place."

Du Plessis argued the science was unclear about the effects of rubbing sweetened saliva on a ball, and said it was impossible to police such a rule given the drinks, sweets and chewing gum players use on-field.

Previous ball-tampering cases have involved the use of dirt, fingernails and beer-bottle tops to rough up the ball and alter its flight in the air.

"I just think it's opened up a can of worms with what's going to happen now going forward with the game," du Plessis said. "Something like this needed to happen to create a bit more awareness around it."

He added: "Obviously the ICC has taken a stance against me, to use me as a scapegoat now. But all I can ask for is that everyone gets treated the same."

It is the second time du Plessis has been fined for ball-tampering, after he was docked 50 percent of his match fee in 2013 for scuffing the ball on the zip of his trousers in the second Test against Pakistan.

However, Du Plessis escaped a ban at Tuesday's hearing and is free to lead the Proteas on Thursday in the third Test against Australia in Adelaide.

'Stay away from mints'

Cricket South Africa chief executive Haroon Lorgat said he would raise du Plessis's case with the International Cricket Council and ask for greater clarity in the rules.

"It's not something new. But it's something that needs to be looked at," he said.

"We will pick this up with the ICC. I understand the cricket committee had already earmarked this particular discussion at their next meeting in May next year," added Lorgat.

Australia skipper Smith also voiced his support for his opposite number, saying: "I think every team around the world shines the cricket ball.

"I've seen Faf's comments and look, from my point of view, and I make it very clear, that we haven't come out and said anything about Faf or about how he was shining the ball or anything like that," Smith said.

"We, along with every other team around the world, shine the ball the same way."

Du Plessis joked that the incident had taken "shine" off South Africa's achievement in thrashing Australia in the opening two Tests, leaving the hosts on the brink of their first ever home whitewash.

With Australia plunged into crisis, chief selector Rod Marsh quit and they will go into Thursday's day-night Test with five changes to their team, including three debutants.

"When you think of Australian cricket teams of past, to see the changes now, that brings pleasure to see what we're doing," du Plessis said.

He said he would continue to shine the pink ball which will be used in this week's day-night Test -- but that he would be careful about sucking mints.

"Probably just for bad breath now, not for shining the ball anymore," du Plessis quipped. "Possibly for this one game I maybe need to stay away from mints."