She was sentenced to five years after being convicted by an Iranian court of plotting to overthrow the Islamic Republic's clerical establishment.
Some critics called for Mr Johnson to resign, but Richard Ratcliffe said it would not be in his wife's interests.
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.
Richard Dalton, the UK's ambassador to Iran from 2003 to 2006, said on Tuesday that the foreign secretary's options are limited and he warned that resolution of the case was unlikely to be swift.
Her family have always maintained she was on holiday with her daughter.
Mrs Zaghari-Ratcliffe worked as a project manager for the Thomson Reuters Foundation, the philanthropic arm of the news organisation. She is now being detained in Iran after being convicted of "spying".
A legal opinion prepared for the human rights charity Redress on Zaghari-Ratcliffe's case said the British government could grant her diplomatic protection as she is "predominantly" a British citizen who has been denied a fair trial.
Consular officials will be at the meeting, along with Middle East minister Alistair Burt, who has already met Mr Ratcliffe and visited Mrs Zaghari-Ratcliffe's family in Tehran.
He will speak to the Foreign Secretary at the Foreign Office at 10am, in a bid to help secure his wife's release from Iran.
Mr Johnson has apologised for the "distress" and "suffering" he had caused with the comments he made at the Commons Foreign Affairs Select Committee on 1 November, and retracted "any suggestion she was there in a professional capacity".
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