The Vatican on Saturday fiercely refuted claims by one of its top officials of widespread corruption and waste in the management of the Holy See, rejecting the accusations as utterly groundless.

"The claims are the fruit of erroneous judgements, or based on groundless fears, openly contradicted by those called as witnesses," the head of the Vatican's governorate, Cardinal Giovanni Lajolo, said in a statement.

Archbishop Carlo Maria Vigano, former secretary general of the governorate and current envoy to Washington, had sent strongly-worded letters warning Pope Benedict XVI of corruption, which were published in January in Italian media.

In a rare public rebuke of another top Vatican official, Lajolo said he was "greatly embittered" by the publication of the letters and accusations made.

"The claims cannot help but give the impression that the Vatican governorate, instead of being an instrument of responsible governing, is an untrustworthy entity, controlled by dark forces," he said.

Lajolo rejected the "baseless suspicions and accusations" the claims had provoked in the media on publication, describing some as "laughable" and pointing the finger at "a certain type of unprofessional journalism."

In extracts from the letters to the pope written in 2011, Vigano said he had faced a "disastrous" situation when he became head of the governorate in 2009 and said his transfer to Washington was "punishment".

"My transfer is causing disarray and discouragement among those who believed it was possible to resolve the numerous situations of corruption and waste" in the Vatican, he said.

Much of his criticism was focused on a Vatican financial committee that includes the head of the Vatican bank, Ettore Gotti Tedeschi. He said the bankers were favouring "their interests" more than the Vatican's.

In one financial operation by the bankers that went wrong, the Vatican made a net loss of 2.5 million euros ($3.2 million), the archbishop said.

He was also highly critical of the cost of basic technical services and said construction contracts for Vatican buildings were always going to the same companies for tariffs that were more than twice as high as in Italy.

He said other cardinals in the Vatican "knew the situation well".