Pope Benedict will be greeted by buses carrying posters calling for the ordination of women during his visit to London in September.
The campaign is being organised by Catholic Women's Ordination (CWO), which has paid around £10,000 for the slogan "Pope Benedict Ordain Women Now" to appear on the famous red 10 buses for one month, from 30 August 2010.
Pope Benedict XVI arrives in Britain on 16 September spending two days in the capital, before moving on to Birmingham and Edinburgh.
The bus posters are due to appear on routes that go past Westminster Cathedral and Westminster Hall. Both venues feature on the papal itinerary.
CWO spokesperson Pat Brown said that a press conference would be held during the papal visit at which the group would make its case for ordaining women.
Last week the Vatican issued a document that dealt mostly with paedophilia, but also stated that the "attempted ordination of a woman" to the priesthood was one of the most serious crimes in church law.
A Vatican official subsequently clarified its position, saying the crimes were of a different nature and gravity - though this did little to assuage the astonishment and anger caused by the statement, which has been seen as another massive 'own goal'.
Catholic Women's Ordination (http://www.catholic-womens-ordination.org.uk/) received more donations and dozens of membership inquiries as a result of the incident.
"We love the church and don't want to be disruptive," said Pat Brown. "We are trying to get support and would love to have five minutes with the pope. We are very concerned about what is going on in the church at the moment."
It is not thought likely that the Pope will be using a bus himself during the course of his trip.
Visit organisers have not yet confirmed whether the famous 'Popemobile' from his predecessor's 1982 visit will be in use, or what advertising opportunities it might afford.
More on Catholic Women's Ordination: http://www.catholic-womens-ordination.org.uk/