Steve Smith and Cameron Bancroft have admitted that Australia attempted to alter the ball during their second Test meeting with South Africa.

Footage emerged of opening batsman Bancroft taking an object from his pocket while shining the ball during day three in Cape Town, before shoving it down his trousers.

Bancroft has since been charged by match officials for his actions, and Smith has now confessed that it was a deliberate ploy taken by the "leadership group" of players in the Australia team.

"The leadership group knew about it, we spoke about it at lunch," he told reporters at a press conference on Saturday. "I am not proud of what has happened. It's not in the spirit of the game, my integrity and the integrity of the team has been damaged and rightfully so.

"It's not on, it's certainly not and it won't happen again under my leadership. We thought it was a possible way to get an advantage, obviously it didn't work.

"It was a poor choice and I deeply regret our actions. I'm embarrassed and I feel for Cam as well. Being the leader of the team, I'm incredibly sorry for, I guess, trying to bring the game into disrepute."

Bancroft added: "I had discussions with the match officials and I've been charged with attempting to change the condition of the ball. I saw an opportunity to use some tape and get some granules from the rough patches on the wicket to change the ball condition.

"It didn't work and the umpires didn't change the ball. I was obviously nervous about it - with hundreds of cameras around there's always a risk. Once I was sighted on the screen I panicked quite a lot and that resulted in me shoving it down my trousers."

The four-match series is currently level at 1-1.