Former Australia wicketkeeper Adam Gilchrist said he was "stunned", "shocked" and "embarrassed" by Steve Smith's admission of premeditated ball-tampering.
Australia captain Smith said he was "incredibly sorry" for bringing the game "into disrepute" after team-mate Cameron Bancroft was caught rubbing a piece of tape, coated with dust from the pitch, on the ball while fielding during the third Test against South Africa.
The scandal has left Smith fighting for his future as skipper - as well as David Warner's position as vice-captain - while head coach Darren Lehmann also faces an uncertain period even though he was absolved of guilt by Smith.
South Africa went on to thrash them by 322 runs to complete a miserable 24 hours but they have lost much more in the last 24 hours, mostly in terms of trust and respect.
Gilchrist told BBC Radio 5 Live: "Stunned and shocked are two words that come to mind and then when you learn more about it I feel embarrassed and sad.
"It's not what should happen. It should not happen. That's the disappointing thing, it's not (a) spur-of-the moment decision. It's not an under-pressure decision where you make a decision and, 'It's okay I got it wrong because of a pressure moment'. It's pre-planned and premeditated. It's just not acceptable."
Gilchrist said he had "the feeling we have been all really badly let down here".
"Steve Smith has said that management were not involved, that the coaches knew nothing about it. It's senior players or a leadership group. I don't remember having a designated leadership group in my time in cricket," he added.
"It contaminates and allows people to speculate on a whole lot of things now. Not just the fact Australian cricket, which has a great deal of pride, is the laughing stock of the cricket, but it allows people to speculate and cast aspirations over other activities.
📺WATCH: Incredible scenes as Australia captain Steve Smith & Cameron Bancroft ADMIT to ball tampering during the Test match with South Africa...
— Sporting Life (@SportingLife) March 24, 2018
🏏How should the @ICC deal with them?#SAvAUS https://t.co/x7sKuMyldG
Kevin Pietersen claimed neither Smith, Darren Lehmann nor bowling coach David Saker could continue in their roles, saying they had "disgraced" their country and the game.
The former England batsman wrote on Twitter: "Slept on it...Lehmann, Saker & the leaderships groups jobs are untenable! "They've disgraced a great cricketing nation & Test cricket!"
Cricket Australia chief executive James Sutherland said: "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."
Australian Prime Minister Malcolm Turnbull branded the actions of Smith and Bancroft "completely beyond belief" and "a shocking disappointment" and called for Cricket Australia, which is investigating the incident, to take "decisive action soon".
"We all woke up this morning shocked and bitterly disappointed by the news from South Africa," Turnbull told reporters in Australia.
"It seemed completely beyond belief that the Australian cricket team had been involved in cheating. After all, our cricketers are role models and cricket is synonymous with fair play.
"How can our team be engaged in treating (cricket) like this? It beggars belief.
"Let me tell you what has happened today from my point of view. I have spoken with David Peever, the chairman of Cricket Australia a few moments ago, and I have expressed to him very clearly and unequivocally my disappointment and my concern about the events in South Africa and he has said to me that Cricket Australia will be responding decisively, as they should.
"It's their responsibility to deal with it, but I have to say that the whole nation, who holds those who wear the baggy green up on a pedestal - about as high as you can get in Australia, certainly higher than any politician, that's for sure - this is a shocking disappointment. It's wrong and I look forward to Cricket Australia taking decisive action soon.
"I think I speak for all Australians in saying how shocked and disappointed we all are. It honestly seems beyond belief. And I have to say, knowing a number of the players, including the captain, quite out of character. But it's been admitted."
England's Alastair Cook has spoken of his sadness at yesterday's events.
"It's sad for cricket," the former England captain told BBC's Test Match Special. "The guys who are in the limelight have a responsibility to play cricket in the right way."
He cites England's current plight against New Zealand, after being bowled out for just 58 on day one of the first Test, as a case in point.
"There are days when things don't go your way - and the first day here in Auckland was a prime example of that - but there is always a way to get back into the game," Cook added.
"We have to play by the rules. As captain, you are responsible for the other 10 guys and are the public figure for that.
"I'm sure Steve Smith is not in a very comfortable position - and in one sense you do feel for him, because I know what the pressure is like as captain of a country.
"You live and die by the sword."
Pundit Michael Atherton said the outrage felt towards Smith and his team by their fellow Australians meant action was inevitable.
Atherton told Sky Sports News: "I've spoken to a couple of people in Australia today and they say they can't remember this level of anger being directed - not just at Steve Smith - but at the cricket team in general."
Atherton was himself accused of ball-tampering during a 1994 Test match with South Africa at Lord's after TV cameras caught him reaching into his pocket and rubbing a substance on the ball. He denied the wrong-doing, claiming that he had dirt in his pocket to dry his hands.
Former Australia fast bowler Jason Gillespie, the Sussex head coach, expects the incident to spark "big changes" on and off the field.
He told Sky Sports: "It's hard to see how Steve Smith can continue as captain of Australia. It's hard to see how David Warner continues as vice-captain.
"Until we've heard from (Australia coach) Darren Lehmann, we won't know any more. He hasn't fronted the media yet, everyone is waiting for that.
"It's hard to think there isn't going to be a fall out and a big change in personnel.
"It appears there's going to be some big changes on and off the field. The Australia side has to have a deep reflection on how they go about the game, how they're perceived in the wider cricketing world. That perception isn't good, that's the brutal reality."
Ex-England captain Michael Vaughan has criticised the "pathetic penalties" handed down to Smith and Bancroft by the International Cricket Council following the incident.
Smith was given a one-match suspension and fined 100 per cent of his match fee for the third Test against South Africa, while Bancroft was fined 75 per cent of his match fee and given three demerit points.
In a series of tweets, Vaughan said: "Pathetic penalties for CHEATING ... Surely this moment was the time to set a precedent ... !!?? All the team should be penalised.
"If you only get a 1 Match ban and hit with a fine over admitting to cheating as an International Captain!! ... If the ICC are going by their list of sanctions against certain actions I think it's time they were updated."
Bancroft has signed to play for county side Somerset this season, lined up to play in both four-day and 50-over cricket.
ICC chief executive David Richardson said in a statement: "The decision made by the leadership group of the Australian team to act in this way is clearly contrary to the spirit of the game, risks causing significant damage to the integrity of the match, the players and the sport itself and is therefore 'serious' in nature.
"As captain, Steve Smith must take full responsibility for the actions of his players and it is appropriate that he be suspended."
"The game needs to have a hard look at itself. In recent weeks we have seen incidents of ugly sledging, send-offs, dissent against umpires' decisions, a walk-off, ball tampering and some ordinary off-field behaviour."
He added: "The ICC needs to do more to prevent poor behaviour and better police the spirit of the game, defining more clearly what is expected of players and enforcing the regulations in a consistent fashion.
"In addition and most importantly Member countries need to show more accountability for their teams' conduct. Winning is important but not at the expense of the spirit of the game which is intrinsic and precious to the sport of cricket. We have to raise the bar across all areas."
In a brief statement released on Sunday, Somerset's director of cricket Andy Hurry said: "I recognise it is important to keep everyone up to date and informed which I will do in due course, however we need to have all the facts and any supporting information before commenting further.
"It will be important to reflect on that information and at that point, I will comment further."
Smith was last month named as captain of the Rajasthan Royals for the upcoming Indian Premier League season.
The Australian Sports Commission, the lead Government agency responsible for Australian sport, said Smith should be removed as captain immediately.
A statement from the commission's chairman John Wylie, the ASC board and chief executive Kate Palmer read: "The ASC condemns cheating of any form in sport. The ASC expects and requires that Australian teams and athletes demonstrate unimpeachable integrity in representing our country.
"The Australian cricket team are iconic representatives of our country. The example they set matters a great deal to Australia and to the thousands of young Australians playing or enjoying the sport of cricket and who look up to the national team as role models.
"Given the admission by Australian captain Steve Smith, the ASC calls for him to be stood down immediately by Cricket Australia, along with any other members of the team leadership group or coaching staff who had prior awareness of, or involvement in, the plan to tamper with the ball.
"This can occur while Cricket Australia completes a full investigation."
In a Royals statement released on Sunday, Rajasthan executive chairman Ranjit Barthakur said: "We have been made aware of the controversy of ball tampering in the ongoing Australia-South Africa series and await further instructions from BCCI [Board of Control for Cricket in India], before we make any announcement.
"We at Rajasthan Royals will not tolerate any actions that are unfair by definition and bring disrepute to the game of cricket. Our Zero tolerance policy applies to everyone in our team. Please bear with us."
