The Catholic Church's national wealth has been estimated at $30 billion.

A Fairfax investigation has found the church is worth more than $9 billion in Victoria alone.

When extrapolated nationwide, the estimate rises to $30 billion.

Property valuations from dozens of Victorian councils have revealed around 1,800 church-owned properties, including churches, presbyteries, schools, nursing homes, hospitals, offices, tennis courts and even mobile phone towers.

The Catholic Church also runs superannuation, telecommunications, Catholic Church Insurance and Catholic Development Funds (its internal treasury).

The figures uncovered in The Age investigation are in stark contrast to the church’s purported wealth.

The Catholic Church told a recent royal commission it was worth just $109 million in Victoria.

Critics have claimed that payouts to the church’s sex abuse victims have been minimised by the church’s protection of its assets.

Francis Sullivan from the Victorian Catholic Church's Truth, Justice and Healing Council denies claims that the church misled the royal commission.

“I think what was presented to the royal commission would have been accurate, all the documents presented by witnesses would have been done so literally, like being under oath,” he said.

“So I don't think there's any gross misrepresentation of the church's position.”

Corporate governance consultant Peter Johnstone, who is also a member of the Catholics for Renewal reform group, said most Catholics would be unaware that the leaders of their faith were so well off.

“Certainly there's been no public record available to Catholics,” he told the ABC.

“I think if anything, The Age has identified a conservative estimate of the worth of the church.

“But they have of course focused on assets as such. There's a lot of other secrecy within the church, and that secrecy must be undone.

“Any organisation receiving public funds should be accountable for those funds and the Government in making those funds available should know exactly how they're being spent.”

Melbourne University taxation expert Professor Ann O'Connell says the Catholic Church's tax-free status should be reviewed.

“In terms of accountability, main churches were able to get a concession from the government when it enacted the Australian Charities and Not-for-profit Commission Act so that it's subject to much less reporting, if the entity qualifies as a basic religious charity,” Professor O'Connell told reporters.

“I think in terms of both the royal commission and now the exposure of how much wealth the Catholic Church has got, I think there might be grounds for reviewing that exemption as well.”