The report published Sunday by British newspaper The Guardian is based on an American academic's research and claims to cite secret minutes of Shimon Peres' meeting with senior South African officials discussing the issue.
Peres said Israel has never negotiated the transfer of nuclear weapons to South Africa.
"There exists no basis in reality for the claims published ... by The Guardian that in 1975 Israel negotiated with South Africa the exchange of nuclear weapons," the president said in an English-language statement. "Unfortunately, The Guardian elected to write its piece based on the selective interpretation of South African documents and not on concrete facts.
The documents accompanying the story show Peres' signature on minutes from a meeting where the then-defense minister discussed payloads available in "three sizes" — one of several phrases that Peres said The Guardian misconstrued.
The British paper did not call the Israeli government for a response to the article, Peres said, adding that his office "intends to send a harsh letter to the editor of The Guardian and demands the publication of the true facts."
The Guardian claims the documents offer the first documentary evidence of Israel's nuclear program.
Israel has never acknowledged or denied possessing nuclear weapons, though it is universally assumed to have them.
