"She was severely beaten up and tortured until she accepted to appear in front of camera. Her 22-year-old son Sajad and her 17-year-old daughter Saeedeh are completely traumatised by watching this programme," lawyer Houtan Kian said on the newspaper's website.
The lawyer said he feared the Iranian authorities would act quickly to carry out the death sentence, which was reportedly commuted to hanging after an international outcry against her sentence last month.
The Guardian gave no details of where the lawyer was speaking.
Another of her lawyers, Mohammad Mostafaie, fled Iran this month and is now in Norway after Iranian officials issued an arrest warrant for him and detained his wife.
The sentence against Mohammadi-Ashtiani was initially for "having an illicit relationship outside marriage", which drew condemnation from many countries.
But in the interview broadcast on state TV, she said that a man with whom she was acquainted had offered to kill her husband and she let him carry out the crime.
In a separate interview with the Guardian last week, she claimed she had been acquitted of murder, "but the man who actually killed my husband was identified and imprisoned but he is not sentenced to death."
In the earlier Guardian interview, she attributed her treatment by the Iranian authorities to her gender. "It's because I'm a woman, it's because they think they can do anything to women in this country," she said.
Betcha she says something. We'll even begin a watch here to keep an eye out for it.