Sydney: Disgraced Australia cricket captain Steve Smith and vice-captain David Warner stepped down from their roles on Sunday for the remainder of the third test against South Africa following the team's confession to ball tampering.

Smith and Warner would still play for the final two days of the test at Newlands, but they would have no leadership responsibilities, Cricket Australia said. Tim Paine would stand-in as captain of the team, CA chief executive James Sutherland said in a statement.

The long-term futures of Smith and Warner are surely in the balance after the captain confessed that he was part of a group of senior players who hatched a plan to cheat against South Africa on Day 3 of the test on Saturday by tampering with the ball.

It appears Warner was also part of the "leadership group" that came up with the plot, although Smith refused to name other names.

Young batsman Cameron Bancroft, who has been charged with ball tampering by the International Cricket Council, was the man tasked with carrying out the cheating and also made a public confession alongside Smith late on Saturday.

"This test match needs to proceed, and in the interim we will continue to investigate this matter with the urgency that it demands," Sutherland said in a statement released just before play started on Day 4 in Cape Town. "As I said earlier today, Cricket Australia and Australian cricket fans expect certain standards of conduct from cricketers representing our country, and on this occasion these standards have not been met.

"All Australians, like us, want answers and we will keep you updated on our findings, as a matter of priority."

South Africa leads by more than 300 runs and looks set for a convincing win to move ahead 2-1 in the series with just one more game to play. The Australia team appeared completely dispirited at the start of play on Sunday, shuffling down the stairs to the field with their heads down.

The team's reputation is in tatters after Smith and Bancroft confessed to the cheating in an attempt to get their team back into the match, which was slipping away. They decided to use a piece of yellow adhesive tape to try and pick up loose dirt on the pitch and use it to rough up the ball.

But Bancroft was caught by television cameras during his attempt to tamper with the ball, and then trying to hide the evidence by shoving the piece of tape down the front of his trousers. The overwhelming video evidence forced Smith and Bancroft to come clean in a humiliating confession at the post-day news conference later on Saturday.

Cricket Australia had dispatched a team to investigate the incident.

"The board fully supports the process for an immediate investigation into what occurred in Cape Town," CA chairman David Peever said. "We regard this as a matter of the utmost seriousness and urgency. We will ensure we have all information available to make the right decisions for Australian cricket."