Only about 10% of donations to the pope's main charitable collection, Peter's Pence, which raises some $55 million annually and is specifically advertised as helping the poor, actually go toward that cause, with approximately two-thirds used to fill budget holes in the Vatican's administrative budget, The Wall Street Journal reported Wednesday.

The revelation comes as the credibility of the Vatican's financial management has already taken a beating, with the Holy See in the midst of a scandal over real-estate investments in London.

In addition, the Vatican's deficit last year doubled to more than $76 million on a budget of some $333 million, according to CNBC.

The website for Peter's Pence describes the charity as a way "to help the poor in whatever way is possible," even quoting Jesus in the Gospel of John: "From this, they will all know that you are my disciples, if you have love for one another."

The use of these donations to plug the budget deficit is especially sensitive for Pope Francis, who has called for a "poor church for the poor" and has repeatedly emphasized the church's mission to care for the most vulnerable, according to The Wall Street Journal.

Pope Francis has defended the use of Peter's Pence donations, saying he tries "to make an investment and . . . when there is a need . . . the money is taken and that capital does not devalue, it stays the same or it increases a bit."

However, according to those familiar with the charity, this explanation obscures the fact only about a quarter of the contributions are available for investments after most of the donations are spent on the Vatican's operating costs.

• Pope Replaces Financial Watchdog Head amid Fallout From Raid
• Pope Decries That 'Greed of a Few' Worsens Poverty of Others