South Africa captain Faf du Plessis has been fined 100 per cent of his match fee but will be free to play the third Test against Australia in Adelaide following an International Cricket Council (ICC) hearing into ball-tampering.

Du Plessis, who faced a marathon hearing at Adelaide Oval on Tuesday lasting three hours, was handed the sanction for breaching the ICC code of conduct.

The ICC had cited du Plessis after television footage appeared to show him shining the ball with a mint in his mouth during the fourth day's play in the second Test against Australia in Hobart.

Du Plessis, who pleaded not guilty, has 48 hours to appeal the decision.

It is the second sanction du Plessis has received for ball-tampering, after he was fined 50 per cent of his match fee in 2013 when he was caught rubbing the ball on his trousers pocket zipper during a Test against Pakistan in Dubai.

Du Plessis was found guilty by ICC match referees representative Andy Pycroft of breaching Article 2.2.9 of the governing body's code of conduct.

The ICC released a statement outlining that the decision was based on the evidence given from the umpires, who confirmed "that had they seen the incident they would have taken action immediately".

It was ruled the television footage showed an artificial substance being transferred to the ball.

In addition to the sanction, du Plessis has incurred three demerit points on his disciplinary record.

A suspension will follow if he reaches four or more demerit points during the next 24 months.

The third Test begins on Thursday, with the Proteas holding an unassailable 2-0 lead heading into the series finale.

The Proteas had vehemently denied in the days following the second Test in Hobart, which they won by an innings and 80 runs, that du Plessis had altered the state of the ball.

Initially opener Hashim Amla laughed off the accusations as a joke before du Plessis was charged by the ICC and matters intensified on Monday at Adelaide Airport when Proteas officials clashed with media.

Zunaid Wadee, the Proteas' security official, was attempting to shield du Plessis from questions regarding the controversy when he physically clashed with Nine Network reporter Will Crouch.

Wadee repeatedly pushed, shoulder charged and knocked a microphone from Crouch's hands.

ABC/Wires