President Pieter W. Botha faced a storm of criticism from liberal and conservative politicians today for the secret tape recording of a conversation with the former leader of the opposition, Frederik van Zyl Slabbert.

Slabbert confirmed that a meeting last November had been bugged without his knowledge. The president's office issued a lengthy statement suggesting that it is "normal and accepted international practice" for heads of state to bug their guests.

The transcripts of the tapes were released by Botha in the National Assembly yesterday on the grounds that Slabbert had broken the confidentiality of the talks by disclosing their substance in a newspaper interview. The president argued that Slabbert, who resigned from parliament and as leader of the Progressive Federal Party earlier this month, had misrepresented the conversation.

Slabbert said today that for the president to talk about confidentiality when he had tape-recorded the meeting without informing him "must be surely one of the most extraordinary instances of somebody declaring his commitment to confidentiality."

The statement issued by the president's office said, "It is self-evident and it is normal and accepted international practice, that there should at times be a record of certain important discussions in order that the state president can be informed of what he and those he had spoken to had said."

Perhaps the most striking exchange between the two men, as quoted in the transcripts, dealt with the issue of white sovereignty. Speaking in Afrikaans, Botha is quoted as saying: "I do not want sovereignty for whites in South Africa because that is not politically practical . . . but what I do say is the white's standard of living must be protected; he has a right to bring up a child as he chooses, not to bring his language under threat and his residential areas . . . if these things, if the riches he has collected for himself, if these are taken away from him, then I say we are looking for trouble."

Slabbert is quoted as replying: "No, I cannot see for myself how it can be expected of him to let go of these things voluntarily."

Slabbert said that it was "extraordinary that he Botha now complains about confidentiality when he did not have the common courtesy to tell me that he was bugging a confidential interview that I requested. Anyone in future should know that if they talk to the president of this country the word 'confidentiality' means something special to him."

Botha was criticized by legislators to the right of his National Party as well as members of parliament from the liberal white opposition.

"I strongly disapprove of any such treatment of any interview, especially when it was not stated beforehand," right-wing legislator Andries Treurnicht said, United Press International reported.

[Peter Gastrow, the Progressive Federal Party's national chairman, said recording the conversation demonstrated the "contempt" with which Slabbert was treated by Botha.]