Former Australia vice-captain David Warner has conceded he may never play for his country again after being banned for 12 months, and from captaincy for life, by Cricket Australia for his part in the ball-tampering scandal during the Newlands Test against South Africa.

In a press conference at the SCG where he stuck rigidly to script, Warner accepted responsibility for playing a role in the episode and apologised to supporters, CA, Cricket South Africa and his family. However, he declined to answer questions about how many other members of the team were aware of the plot, whether he had tampered with the ball on previous occasions, whether his relationship with the rest of the team had deteriorated, or whether he was being made a scapegoat for the affair by CA, who handed him the heaviest penalty of all three players.

Less than two hours after the press conference ended, Warner took to Twitter to clarify why he had not answered some questions. "I know there are unanswered questions and lots of them. I completely understand. In time I will do my best to answer them all. But there is a formal CA process to follow," he said on Twitter. "I am taking advice to make sure I properly comply with that process and answer all questions in the proper place and at the proper time. I should have mentioned that in my press conference, I'm sorry for not making it clearer. With so much at stake for my family and cricket, I have to follow this process properly. I think that's fair."

During the press conference, Warner was not asked whether he intended to challenge the charges and sanctions imposed by CA under the code of behaviour. Asked whether he would retire from the game, Warner said he was considering all his options with his family.

After about six minutes of questions, Warner left the room with plenty more hanging in the air. Warner, the captain Steven Smith and Cameron Bancroft have until Tuesday to inform CA of whether they wish to take the matter to a hearing before an independent commissioner, and all are understood to have retained legal counsel while weighing this up.

For Warner, who struggled at times to control his emotions, the most telling line of his prepared statement was that he was "resigned" to the fact he might never again play for Australia, and that he was committed to changing himself as a person.

"It is heart-breaking to know that I will not be taking the field with my team-mates I love and respect and that I have let down," Warner said. "Right now it is hard to know what comes next, but first and foremost is the wellbeing of my family.