The Catholic Archbishop of Bamako in Mali, Jean Zerbo, denies holding Swiss bank accounts containing $13.5m (£10m)
The archbishop's name appears in SwissLeaks documents scrutinised by the French newspaper, Le Monde.
The revelation is an embarrassment both to the Catholic church in Mali and to the Vatican. Last week, Pope Francis named Archbishop Zerbo among five new cardinals.
Le Monde reports that seven accounts were opened in Monaco in 2002. These are now with the HSBC Private Bank in Geneva and are still active.
In a statement, Mali's bishops conference says the report is false and that no churchgoers' gifts have been diverted overseas.
Bamako Cathedral is rundown. It has been raising funds for a new roof for years. Services are often held in a nearby car park.
Confronted by a reporter, the archbishop denied being among three Malian churchmen linked to the Swiss accounts.
He said any overseas money was inherited from French colonial missionaries.