The budget for the papal visit to Geneva has already exceeded two million francs, according to the Catholic media centre Kath.ch.
This is as much as the total annual outlay of the bishopric of Lausanne, Geneva and Fribourg, which is expected to cover the costs of the Pope's one-day visit on June 21st.
“We haven't got the budget under control,” admitted the diocesan treasurer Jean-Baptiste Henry de Diesbach as he launched a last-minute appeal for donations.
De Diesbach said around 15 parishes had donated on average 1,500 francs, but this was not enough.
He is now trying to mobilize parishes to make up the shortfall, estimated at 1.5 million francs.
Security surrounding the visit will cost one million francs, with infrastructure and audiovisual costs accounting for a further million.
The Pope is to hold a mass at the Palexpo convention centre in Geneva at 5.30pm next Thursday.
The last papal mass in Switzerland, presided over by Pope John Paul II in Bern in June 2004, attracted 70,000 people.
Pope Francis is visiting Switzerland to attend a meeting of the World Council of Churches, which represents around 500 million Christians globally.
He will fly out of Geneva on Thursday evening following the mass.