Mohammadi Ashtiani's stoning has been approved by Iran's supreme court.

However under Iranian law the head of the judiciary can order another trial or appeal for a pardon from Ayatollah Ali Khamenei, Iran's supreme leader, who has final say on all state matters.

Murder, adultery, rape, armed robbery, apostasy and drug trafficking are all punishable by death under Iran's sharia law, enforced since the 1979 Islamic revolution.

For sentences of stoning a man is usually buried up to his waist, while a woman is buried up to her chest with her hands also buried.

Those carrying out the sentence then throw stones until the condemned person dies.

Amnesty International, one of several groups publicising her case, said last week that Mohammadi Ashtiani, who has two children, was convicted in 2006 of having an "illicit relationship" with two men and received 99 lashes as punishment.

The group said that despite that sentence she was subsequently convicted of "adultery while being married", and was sentenced to death by stoning.

The European Union, US and British governments have all appealed for a stay of execution.

At least 10 other people, including seven women, are under sentence of stoning in the Iranian jails, Amnesty said.