Sakineh Mohammadi Ashtiani is already behind bars, serving a 10-year sentence on a separate conviction in the murder of her husband. Amid the international outrage her case generated, Iran in July 2010 suspended plans to carry out her death sentence on the adultery conviction.
On Sunday, a senior judiciary official said experts were studying whether the punishment of stoning could be changed to hanging.
"There is no haste. ... We are waiting to see whether we can carry out the execution of a person sentenced to stoning by hanging or not," said Malek Ajdar Sharifi, the head of justice department of East Azerbaijan province, where Ashtiani is jailed.
"As soon as the result (of the investigation) is obtained, we will carry out the sentence," he said, according to the semi-official ISNA news agency.
The charge of a married woman having an illicit relationship requires a punishment of stoning, he said.
He said judiciary chief Ayatollah Sadeq Larijani ordered a halt to stoning in order to allow Islamic experts to investigate whether the punishment can be altered in Ashtiani's case.
Ashtiani was convicted of adultery in 2006 after the murder of her husband.
She was later convicted of being an accessory to her husband's murder and sentenced to 10 years in prison.
May 2006 Sakineh Mohammadi Ashtiani Ashtiani found guilty of adultery by a court in Tabriz, north-west Iran, and ordered to receive 99 lashes, a sentence carried out in the presence of her 17-year-old son.
September 2006 Ashtiani's case is reopened when the Tabriz court supects her of involvement in the death of her husband. She is acquitted, but the judge reviews the earlier adultery charge and sentencs her to death by stoning.
July 3 2010 The Guardian breaks the story of the international campaign mounted by the children of Sakineh Ashtiani.
July 22 2010 Malek Ajdar Sharifi, the senior judicial official in East Azerbaijan province, where the mother-of-two was convicted, tells the state news agency that the sentence "will not be implemented for the time being".
July 26 2010 Sakineh's lawyer, Mohammad Mostafaei, is arrested in Tehran along with his wife and brother-in-law.
August 2 2010 Brazilian president Luiz Ignacio Lula da Silva offers Sakineh asylum during a speech at a rally in southern Brazil.
August 7 2010 Guardian runs an interview with Sakineh from inside prison in which she accuses the Iranian authorities of lying about the charges against her in order to pave the way for her execution.
August 12 2010 Sakineh appears on Iranian state TV to confess to adultery and complicity in the murder of her husband. Her lawyer tells the Guardian that his client has endured two days of torture to force her to make the confession.
August 28 2010 The house of Sakineh's government-appointed lawyer, Houtan Kian, is ransacked as Sakineh's children are refused permission to visit their mother in prison.
September 16 2010 Sakineh again appears on state TV, denying that she has been tortured or coerced in any way. She also denied reports that she had received a further 99 lashes while in prison.
September 29 2010 The Iranian government indicates that Sakineh may be hanged rather than stoned to death.
October 10 2010 Sakineh's son, Sajad Ghaderzadeh, is arrested with two German journalists who interviewed him in Tabriz. His mother's lawyer, Houtan Kian, is also detained.
November 16 2010 Appearing on TV for the third time, Sakineh reiterates her previous televised "confessions", including that she was involved in the murder of her husband. "I am a sinner," she says.
November 23 2010 Mohammad Javad Larijani, head of Iran's High Council for Human Rights, says Sakineh may be spared execution by stoning.