Australia's financial watchdog is reviewing its calculation that transfers worth $US1.8 billion ($A2.3 billion) had been sent to the country from the Vatican since 2014, after Vatican and Australian Church calls for clarification.
A senior Vatican official and an Australian bishop told Reuters last week they had no knowledge of the transfers and would be seeking clarification.
The Australian Transaction Reports and Analysis Centre (AUSTRAC) cited the amount in response to a parliamentary question by Australian Senator Concetta Fierravanti-Wells.
AUSTRAC said about 47,000 separate transfers were involved.
After the Vatican said it was "stunned" by the figures, the Australian financial watchdog said on Thursday: "AUSTRAC is currently undertaking a detailed review of the figures and is working with the Holy See and Vatican City State Financial Intelligence Unit on this matter."
A source familiar with recent exchanges said AUSTRAC had contacted the Vatican's financial watchdog and was looking into "the integrity of the data" it used to calculate its figures.
AUSTRAC said in response to Fierravanti-Wells' question that the transfers ranged from yearly totals of $A71.6 million in 2014 to $A581.3 million in 2017.
"That amount of money and that number of transfers did not leave the Vatican City," a senior Vatican official with knowledge of the city-state's finances told Reuters last week.
Archbishop Mark Coleridge of Brisbane said the Australian Church was not aware of any such transfers, that the money did not go to a diocese or Church entity in the country and that the bishops would be seeking clarification from the Vatican and AUSTRAC.
Fierravanti-Wells had asked what funds had been transferred to Australia "from the Vatican or any of its entities, or individuals associated with the Vatican or Vatican entities" since 2014.
The Vatican has more than 100 legal entities including hospitals and other bodies in Italy and elsewhere.
An outside financial expert with experience in direct dealing with Vatican finances said the question posed by the senator was so broad that only a comprehensive review could shed light on where the money came from and where it wound up.
The expert, who spoke on condition of anonymity, said that it was surprising red flags had not come up before for such large yearly amounts and that much depended on the methodology used to track the transfers.