Dubai Police detained her in the United Arab Emirates last month with her 14-year-old daughter Paris at the Dubai airport. The charges relate to two comments she posted under photos of her former husband on his Facebook account.
"When Laleh told them she can't afford to stay in even a cheap hotel while she waits and is in danger of becoming homeless in Dubai", she said.
When she and her daughter returned to London, her husband filed for divorce and remarried shortly afterwards, the campaign group says.
One of the offending comments, written in Farsi, said: "I hope you go under the ground you idiot".
"We flew to Dubai where we were intending to stay for just five days and were arrested immediately upon entry because Pedro's [her ex-husband] new wife Samah had reported my old Facebook post to the police", Ms Shahravesh said in a statement published by Detained in Dubai.
Under Dubai's cybercrime laws, people who visit the desert state can be heavily fined and jailed for social media posts made before they visit, the campaign group warns.
Ms Shahravesh had been married to her ex-husband for 18 years and the couple had lived in Dubai for an eight-month period. We are so close, especially since her father left us and we only have each other. In this country, your Facebook comments can take you to jail.
Ms Shahravesh was in Dubai with her daughter, to attend her ex-husband's funeral, who had died of a heart attack.
Earlier, Ms Stirling told BBC News that both her organisation and the Foreign Office (FCO) had asked the complainant to withdraw the allegation, but she had refused.
She said: "We were married for 18 years after all".
"All she wants is to be reunited with her mother". "But I don't know anyone here well enough for that. I have been to court once, where I was not allowed to defend myself". "Not only has Paris lost her father, but in going to visit him to say her final goodbye, she wound up in a frightening Middle Eastern police station, and is now without her mother". "Eventually they let us go, but kept my passport".
A British Foreign Office spokesman said its staff were supporting a British woman and her family following her detention in the United Arab Emirates.
Stirling added that the decision "seems quite vindictive".
Detained in Dubai said her ex-husband reported the comments to the authorities.
Detained in Dubai founder Radha Stirling said the UAE's cybercrime laws "apply extraterritorially and retroactively", exposing unwitting travellers to prosecution.