Prime Minister John Vorster of South Africa said in an interview broadcast yesterday that he did not promise President Carter his country would not develop nuclear weapons.

"I am not aware of any promise that I gave to President Carter," Vorster said on "Issues and Answers" (ABC. WJLA). "I repeated a statement which I have made very often that, as far as South Africa is concerned, we are only interested in peaceful development of nuclear facilities," he said.

On Aug. 23 President Carter announced that South African officials had told him: "They do not have and do not intend to develop nuclear explosive devices for any purposes, either peaceful or as a weapon . . ." the President, then added, "We appreciate this commitment from South Africa."

Reports in early August that the White minority government of South Africa was planning to test a nuclear device alarmed many nations. South Africa vigorously denied the reports, the first of which was published by Tass, the Soviet news agency, on Aug. 8.

But suspicions were raised when American and Soviet reconnaissaince produced photographs of a potential nuclear test site in the Kalahari Desert region of South Africa near the Southwest African (Namibian) border.

The Soviet Union, the United States, Great Britain, France, West Germany and other countries worked in concert to try to prevent South Africa from entering the world's nuclear club. Many of the nations feared that South Africa's detonation of a nuclear device would be done in defiance of world condemnation of its racial policies, and would endanger international peace and security.

President Carter called on South Africa to sign the nuclear nonproliferation treaty, which is designed to prevent the spread of nuclear weapons. But Vorster said in the interview yesterday that his country wants "certain guarantees before we sign that treaty and until such time as we have those guarantees, then the status quo will remain."

The prime minister's comments on the treaty came at the end of the interview and there was no time for elaboration on his request for "certain guarantees" and his meaning of "status quo."

"Unfortunately, that is always the case. We run out of time." Vorster said in conclusion.

The White House declined comment on Vorster's statements, which were taped last Monday in Pretoria - two days before Vorster's cabinet banned major black organizations, including the largest black newspaper, and ordered mass arrests of opponents of the South African system of racial separation.

As if anticipating the heightened criticism those actions would, and did, engender, Vorster said in the interview that his countrymen are "prepared to stand alone if we must" in carrying out the nation's racial policies.

The prime minister was especially critical of the "meddling" of the United States and the Soviet Union in South Africa's affairs.

"It appears to us at the moment (that) the Soviets want to kill us off by force and the United States wants to "strangle . . . with finesse" began with the Carter administration, and has manifested itself economically in South Africa.

"We have had actual cases where people have told us straight out that they were under terrific pressure" from the U.S. government to withdraw investments from South Africa, Vorster charged.

He added: "You know we can't force people to do business in South Africa and if their governments make it impossible for them to carry on business in South Africa, then I take it . . . they will stop, leave a vacuum, and somebody else will flow into that vacuum."