Not exactly cricket.

Cameron Bancroft will have questions to answer after an alleged ball-tampering incident during day three of third Test between South Africa and Australia in Cape Town.

The Australian opener appeared to rub the ball with a yellow item, which was then returned to his pocket before being dropped down the front of his trousers. 

Bancroft produced a black sunglasses carrier when pressed over the incident by the umpires, appearing to imply that the case was the only item in his pocket.

Spectators speculated on social media that the item used and then swiftly hidden by Bancroft was sandpaper, although there is no concrete evidence to confirm whether that was the case.

The incident is the latest in a string of controversial moments that have blighted the four-match cricket series.

David Warner was in the headlines during the first Test in Durban after becoming involved in a heated exchange with South Africa's Quinton de Kock as the teams left the field for tea on day four.

It was alleged the wicketkeeper had made personal comments regarding Warner's wife, and the ICC docked the Australian 75 percent of his match fee and gave him three demerit points, while De Kock was fined 25 percent and received one demerit point.

In the second Test in Port Elizabeth, Kagiso Rabada risked disciplinary action by brushing shoulders with Steve Smith having dismissed the Australia captain.

Rabada was initially suspended for two games — the remainder of the series — but appealed and that decision was overturned.

Warner then appeared to become embroiled in a verbal spat with a spectator as he left the field Friday after being clean bowled by Rabada.

Faf du Plessis was found guilty of ball-tampering during a 2016 series between the two sides, when he applied saliva to the ball with a sweet in his mouth.

The South Africa skipper was fined his full match fee and given three demerit points over the incident.