A distraught Steve Smith broke down in tears while speaking about his involvement in the ball-tampering scandal that has rocked Australian cricket during an extraordinary press conference in Sydney.

The disgraced Australia captain had been sent home from the South Africa tour for his role in orchestrating a ball-tampering plot during the third Test against South Africa in Cape Town.

He was handed a one-year ban from international cricket by Cricket Australia as a result of the scandal and barred from holding any leadership position in the Australian team for a period of two years.

Addressing Australian media after landing in Sydney Airport, Smith broke down repeatedly during the course of his press conference.

"To all of my teammates, to fans of cricket all over the world and to all Australians who are disappointed and angry. I'm sorry," he began.

"I take full responsibility. There was a failure of leadership, of my leadership. I'll do everything I can to make up for my mistake and the damage it's caused.

"If any good can come of this, if there can be a lesson to others then I hope I can be a force for change," Smith added.

"I know I'll regret this for the rest of my life. I'm absolutely gutted. I hope in time I can earn back respect and forgiveness.

"Cricket is the greatest sport in the world. It's been my life and I hope it can be again. I'm sorry and I'm absolutely devastated."

Steve Smith
Steve Smith has been banned from playing for Australia for 12 monthsAFP/Getty Images

Cricket Australia's investigation found that vice-captain David Warner was the instigator of the plot to tamper the ball, which was carried out on the field by Cameron Bancroft, while Smith was charged with having knowledge of the plan but failing to stop it.

Smith said he did not blame any of his teammates for his plight, adding that ultimate responsibility for the conduct of the Australian cricket team rests with him as he was the captain.

He said: "I'm deeply sorry. I love the game of cricket. I love entertaining young kids. I just want to say sorry for the pain I've brought to Australia, to the fans and the public."