The Foreign Secretary was also urged in the House of Commons on Monday to contemplate whether Pope Francis might be able to help free the jailed Briton.
Appealing to Boris Johnson, Tom Tugendhat MP (pictured above) said: "Would he consider calling upon people in our system who may be able to talk to the mullahs, perhaps asking the Archbishop of Canterbury, or indeed the Holy Father, to speak on behalf of this woman and seek to broker her release?"
The conservative representative for Tonbridge and Malling spoke after Mr Johnson restated the Government's plea that Iranian authorities release Mrs Zaghari-Ratcliffe on humanitarian grounds.
Ministers say the mother of one was detained in April last year after visiting relatives in Iran and subsequently jailed for five years after being accused of plotting to overthrow the Islamic Republic.
Mr Johnson told the chamber he will meet with Mrs Zaghari-Ratcliffe's husband on Wednesday to discuss whether she might be offered "diplomatic protection" in a bid to secure her safe return.
During the session, Boris Johnson also apologised for previously telling a Commons committee that she was training journalists, a move which appeared to risk seeing her jail sentence being doubled.
Boris Johnson retracted his statement in the House of Commons yesterday.
Some Labour MPs chanted "resign" as he took questions in the chamber.
Responding to Mr Tugendhat, he said: "I assure him that no stone will be left unturned in our efforts."