The Vatican may have been "swindled" by pervious property investment advisors, the city-state's chief finance minister has revealed. 

Jesuit Fr. Juan Antonio Guerrero Alves, head of the Vatican's Secretariat for the Economy, made the shocking admission as the Vatican issued its first budget document in more than five years. 

Speaking to the Vatican News, Alves said it was "possible that in some cases the Holy See has been more than poorly advised, but also swindled" and vowed to usher in a new era of transparency regarding the Vatican's finances.

"The faithful have a right to know how we use the resources of the Holy See," he said, adding that the Vatican "must be a house of glass". 

The Vatican's financial dealings have come under increased scrutiny in recent weeks after the resignation of senior official Cardinal Angelo Becciu amidst a series of allegations related to financial mismanagement. Becciu, once the second-most senior figure in the Vatican's Secretariat of State, was criticised for using church funds to buy a £155m apartment block in Sloane Avenue, London.

The purchase was intended as an investment, but eyebrows were raised when financial records revealed that the Church funding had come through offshore funds and companies.

Five officials from the Secretariat of State were suspended last year after the Vatican Bank opened up an investigation into the financial operations overseen by Becciu. 

The latest budget documents reveal that the Vatican boasts an asset portfolio valued at around $4 billion.