South Africa consider the ball-tampering allegations against Faf du Plessis to be "ridiculous," and "a joke," and believe their stand-in captain has done "absolutely nothing wrong." That was the message from the team's senior-most batsman Hashim Amla, who addressed the media at the MCG on Friday afternoon, accompanied by the entire South African squad and support staff, who were present to "show solidarity".

Du Plessis was among the group but stood in the background and was not put up to answer any questions. Instead Amla, the designated player for Friday's media opportunity, began in the unusual fashion of delivering a mini-speech to open proceedings.

"Good afternoon everybody. As you can see we have the full team here behind us," Amla said. "The reason everybody is here is to stand together and to show solidarity to what has been something we actually thought was a joke. It's not April. But the allegations against Faf were really, for us, a ridiculous thing and as a team we are standing strong. For us it is basically a joke. The boys are here, standing strong."

At the time, Amla was not aware that the ICC was reviewing footage of du Plessis shining the ball after licking his fingers when there appeared to be a sweet in his mouth. "Is it?," Amla asked when told about the governing body's investigation. "Whether it is or not, we've done nothing wrong and Faf has done absolutely nothing wrong."

Part of South Africa's defence is that players often have something in their mouths on the field, Amla included. "I chew bubblegum while I am fielding. Do you want me to brush my teeth after lunch every time I come out?" he said. "You've got to be logical about this, common sense surely should prevail. If I've got something in my mouth, guys are handing out red froggies at lunch time to give the kids, keep them hydrated, energise them and we are in the field for two hours. We eat nuts, biltong, that sort of thing. There was no malicious intent."

Amla said he was unaware that sugary sweets have been used to shine one side of the ball in order to get reverse swing, as Marcus Trescothick wrote in his autobiography. "Is that a tactic?" Amla asked. "Is it proven or what? That's something that's new to us. I've had sweets in my mouth, bubblegum in my mouth, biltong, nuts, I'm not sure what the big deal is. Are you sure it (an advantage) can be gained? We don't know. I can only speak for what my captain has done."

Amla went as far as to say the reaction to the footage could be an attempted to discredit South Africa's dominance in the series. "To me and to a lot of people, it is sounding like sour sweets for people in their heads that we've played really good cricket and the timing of it is that it's a bit weird too," he said.

The visuals emerged the day after the Hobart Test, which South Africa won by an innings and 80 runs to take the series 2-0. Du Plessis had not been reported by the match officials and the ICC were only alerted to the alleged tampering through media reports and then chose to review it of their own volition.

Amla maintained that the entire South African camp were convinced of du Plessis' innocence. "I am just trying to clear what we think is an absolutely wrongful allegation made on our captain. We are standing in solidarity to our captain who has done absolutely nothing wrong. It's pretty clear what we are trying to do you here. As I said, we've done nothing wrong. If there was any doubt whatsoever, you wouldn't have the full team here. We've just basically done nothing wrong."

Less than two hours after Amla spoke, du Plessis was formally charged and pleaded not guilty. South Africa are awaiting legal counsel before a date for the hearing can be decided so it is uncertain whether it will take place before the Adelaide Test next Thursday. If found guilty, du Plessis could face a suspension of one Test.