Oslo's prosecutor accused the Catholic Church in the Norwegian capital on Thursday of defrauding the state of 50 million crowns ($6.57 million) by falsely claiming aid.
Religious organizations can receive an annual contribution from the state, but police in Oslo say the Catholic Church there inflated congregation numbers to massively increase the amount it could claim.
The church declined to comment, and said it would release a statement later on Thursday.
"The fraud happened when they enrolled people in a register without the members actually knowing they were being enrolled in the church," Oslo's police prosecutor, Kristin Rusdal, told Reuters.
"Using this register they applied for funding from the state and municipalities, which is distributed on the basis of how many members the church have," Rusdal said.
Police are investigating the church, its finance director and the bishop of Oslo.
Roman Catholic Church membership in predominantly protestant Norway increased to 140,000 last year from 67,000 in 2010, according to Statistics Norway.