Sakineh Mohammadi Ashtiani is already in prison serving a ten-year sentence on a separate conviction for the murder of her husband.
Ashtiani was to be stoned to death in Iran on an adultery conviction could be hanged instead.
Her case has generated international outrage and last July Iranian officials suspended plans to carry out her death sentence on the adultery conviction.
A senior judiciary official said experts were studying whether the punishment of stoning could be changed to hanging.
Malek Ajdar Sharifi, the head of justice department of East Azerbaijan province, where Ashtiani is jailed said: ‘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.
‘As soon as the result (of the investigation) is obtained, we will carry out the sentence.’
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.
She was sentenced to death by stoning for adultery after suffering years of abuse at the hands of her drug addict husband.
Ashtiani’s lawyer said she was allegedly beaten and sold for sex by opium-addict Ebrahim Ghaderzade.
She was jailed for ten years for murder and sentenced to death for adultery. She was also convicted of having illicit relations for which she received 99 lashes.