2:06 Darren Lehmann hopes people will forgive the banned trio after the ball-tampering scandal Darren Lehmann hopes people will forgive the banned trio after the ball-tampering scandal

Australia head coach Darren Lehmann says he is worried about the fragile mental state of the players suspended over the ball-tampering scandal.

An emotional Lehmann, cleared of any wrongdoing by a Cricket Australia (CA) investigation, broke his silence on Wednesday, insisting the banned trio Steve Smith, David Warner and Cameron Bancroft were "not bad people" and should be given a second chance.

He also said the team would need to improve their behaviour on and off the pitch to win back fan respect after Bancroft was caught tampering with the ball with sandpaper in the 322-run third Test defeat by South Africa.

"The players have made a grave mistake but they are not bad people," Lehmann said.

"There is a human side to this. They are hurting and I feel for them and their families. These are young men and I hope people will give them a second chance. Their health and well-being is extremely important to us.

"I worry about the three guys immensely. We love all of our players and they are going through a really tough time.

"We know we have let so many people down. We are truly sorry. There is a need for us to change the way we play. We need to work to bring the respect back from the fans."

0:35 Steve Smith had to fight through Johannesburg airport on his return to Australia Steve Smith had to fight through Johannesburg airport on his return to Australia

With Smith, Warner and Bancroft sent home from South Africa ahead of the fourth and final Test in Johannesburg, Lehmann remained in charge because Cricket Australia said he was unaware of the plot to tamper with the ball.

Bob Willis said it is "almost unbelievable" that Lehmann was unaware of the ball-tampering ploy, and some media reports suggested the head coach would step down.

However, early on Wednesday, CA chief executive James Sutherland confirmed Lehmann had no involvement or prior knowledge of the plan to alter the condition of the ball

0:35 Cricket Australia chief James Sutherland says Lehmann did not know anything about the ball-tampering plan Cricket Australia chief James Sutherland says Lehmann did not know anything about the ball-tampering plan

In video footage from the third Test in Cape Town, Lehmann can be seen communicating with 12th man Peter Handscomb, who then runs onto the pitch with a message for Bancroft.

Sutherland insisted Lehmann was innocent and said: "I want to say that he sent a message to say 'What in the hell is going on?' He didn't use hell, he used another word.

"I want to make that point very clearly that Darren made those comments and Iain (Iain Roy, head of Integrity) was certainly satisfied that Darren wasn't involved and didn't know anything about the plan."

Lehmann and Smith in happier times after Australia won the Ashes

The coach revealed how he initially knew of the ball-tampering at Newlands and said he was confident it was a one-off incident and had not been part of the team's playing culture in the past.

"The first I saw of it was on that screen, I got straight on the walkie-talkie and said something," he added.

"There were a couple of expletives in there. Then I spoke to the players at tea time and said we would deal with it at the end of play, which happened through the process.

"I am confident it is an isolated issue and a grave mistake. Its never happened before in speaking to those guys."

Contrary to some reports, Lehmann insisted the trio had the backing of the entire team.

0:39 Bob Willis says Lehmann is lucky to keep his job as head coach after the scandal Bob Willis says Lehmann is lucky to keep his job as head coach after the scandal

"When you lose three men in your team, who obviously made a mistake, that hurts all of us. Saying goodbye to them is difficult," he said.

"The whole group is upset and we understand the enormity of it and the public perception. We have to try and win the fans back over and play the best cricket we can.

"If we take a leaf out of someone like New Zealand... we push the boundaries on the ground, so we need to make sure we are respecting the game and its traditions."

On the future of Smith, Lehman said: "He is going to come back a better person, there is no doubt about that."