The group that commissioned the reports has a bias: lawyers representing the political party of an ousted president, Mohamed Morsi of the Muslim Brotherhood. Mr. Sisi, then the top general, removed Mr. Morsi in a military takeover in 2013. The lawyers are trying to use the recordings as evidence in a criminal case in Britain charging the takeover’s leaders with torture and other human rights violations.

But many Egyptian intellectuals and Western and Arab diplomats in Cairo say they have already come to accept the recordings as authentic, if only because of the increasingly pro forma nature of the government’s denials. More than two hours of recordings have been leaked since fall.

After quickly dismissing the first leaks as fabricated, the government has scarcely bothered to dispute the others. Spokesmen for the president, the Defense Ministry and the Foreign Ministry declined to comment or to return phone calls for this article.

Commentators considered sympathetic to Mr. Sisi have shrugged off questions. “Everyone records during the time of chaos,” Mohamed Hassanein Heikal, the dean of Egyptian journalists, who was former President Gamal Abdel Nasser’s confidant, said of the leaks in a television interview a few months ago.

Others say the existence of the leaks is more embarrassing than the content. “It does not just tell us that there are divisions on the inside,” argued Rabab el-Mahdi, a political scientist at the American University in Cairo. “It also tells us that they are so incompetent, to allow these recordings inside the Defense Ministry for such a long span of time.”