Cardinals from all over the world began voting Wednesday to elect a new pope -- but what's the cost of finding a new leader for the Catholic Church?

The Holy See has not disclosed how much the conclave will weigh on its shaky finances. But arranging it is understood to be an expensive affair, running into the millions of euros.

More than 200 cardinals with assistants in tow have been flown in from across the globe, housed, fed and laundered for days following the death of Pope Francis on 21 April.

On Wednesday afternoon some 133 of them -- those aged under 80 -- began voting for a new pope under Michelangelo's frescoes in the Sistine Chapel, which has been fitted out to hold the gathering.

So has St Peter's Square, where thousands of faithful and curious tourists are expected to watch for the white smoke that signals to the world the election of a new pope.

As per the 1929 deal that created the Vatican City State, Italy foots the bill for security costs.

During the last conclave in 2013, security, increased public transport and other related expenses came to 4.5 million euros ($5.1 million), according to then Rome mayor Gianni Alemanno.

This year, the hard-right government of Prime Minister Giorgia Meloni made available an initial five million euros after Francis's death but total costs are yet to be quantified, said civil protection minister Nello Musumeci.

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Almost 12,000 security staff, 1,000 firefighters and 5,000 civil servants were deployed between the death of John Paul II and the election of Benedict XVI in 2005, according to the government.

That year, arranging the funeral and the conclave cost the Vatican some seven million euros, according to a report published by the Holy See.

The Church has since been less transparent with figures.

In 2013 it provided no total cost for Pope Francis's conclave, but the Vatican later reported an annual budget deficit of 24 million euros.

Similarly no estimate has been given for this conclave.

After Francis's death, Vatican spokesman Matteo Bruni only pointed out that the Holy See had no "sponsors" helping with money matters.

During his pontificate, the Argentinian sought to clean up the murky and often disastrous financial affairs of the Holy See.

He created a special secretariat for the economy in 2014, clamped down on corruption and stepped up scrutiny of investments and the Vatican Bank, which led to the closure of 5,000 accounts.

But Vatican finances remain precarious and cardinals were briefed on the situation ahead of the conclave.

The Holy See continues to face a chronic budget deficit, estimated at around 30 million in 2022, amid a decline in donations from the faithful.