Larijani said the judiciary supports the principle of stoning despite international condemnation.
Larijani's remarks also come amid an investigation by the judiciary authorities themselves into whether the stoning -- which was ordered by a local judge to be carried out -- violated a 2002 directive by judiciary head Ayatollah Mahmud Hashemi-Shahrudi against carrying out the practice.
When asked about the Shahrudi directive, Larijani called stoning a feature of Shari'a law and claimed that "Mr. Shahrudi is not opposed to the principle of a...verdict that is based on Islamic Shari'a," according to AFP.
The stoning to death of Jafar Kiani in the northwestern province of Qazvin was the first time Iranian officials had confirmed such an execution in five years.
Kiani's former partner and the mother of their two children, Mokarameh Ebrahimi, reportedly remains in jail.
International rights activists have expressed urgent concerns that officials might try to impose Ebrahimi's sentence, too, and called for Iranian authorities not to execute her.
Ayatollah Hossein Ali Montazeri, a dissident cleric who is a prominent Iranian source of emulation, pointed out to Radio Farda in a written statement on July 12 that adultery is difficult to prove under Islamic law and applicable only to cases under "certain conditions." He also said that "executing this sentence under the sole discretion of the local judge is problematic," adding that "what happened recently in Takestan has been in violation of the standards of law."
Montazeri said that "if at any time or in any place such an execution leads to a weakening of faith, it must not be carried out."
Montazeri argued that stoning sentences are simply meant to be a tool to create fear and discourage sin.
Mohammad Javad Larijani is the brother of Iran's top nuclear negotiator and Supreme National Security Council secretary, Ali Larijani.