The posters planned by Catholic Women’s Ordination (CWO) display the slogan “Pope Benedict Ordain Women Now”, according to the Guardian.
The £10,000 campaign will run on 10 buses for one month, starting on August 30.
It includes buses running on routes that pass Westminster Cathedral and Westminster Hall, where the Pope is due to make stops during his four-day visit in September.
CWO member Pat Brown defended the campaign: "We love the church and don't want to be disruptive. 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."
News of the campaign comes just one week after the Vatican came under fire for according child abuse and the ordination of women the degree of seriousness in a new Church document.
The revised "Rules on the Most Serious Crimes” relate to abusive priests, the ordination of women as priests, heresy, and apostasy.
Buses have recently become something of a battleground for atheists and believers, after prominent atheists Ariane Sherine and Richard Dawkins ran a bus campaign proclaiming “There’s probably no God. Now stop worrying and enjoy your life”.
It was soon followed up by an advertising campaign run by the Christian Party stating “There definitely is a God. So join the Christian Party and enjoy your life”.
The Pope will be in Britain from September 16 to 19. During his state visit, the Pope will meet the Queen, religious leaders and beatify Cardinal John Henry Newman.