There are calls for the Catholic Church's tax-free status to be reviewed after a Fairfax investigation revealing the extent of property, assets and investments owned by the church in Australia.

Key points: Probe indicates the Catholic Church is worth more than $9bil in Victoria alone

Probe indicates the Catholic Church is worth more than $9bil in Victoria alone Reported figures are in stark contrast to what is on the public record

Reported figures are in stark contrast to what is on the public record Academic calls for the Church's tax free status to be reviewed

Fairfax's six-month investigation found the Catholic Church was worth more than $9 billion in Victoria alone.

The investigation extrapolated that figure to estimate the church's national wealth at $30 billion.

The Age's journalists obtained property valuations from dozens of Victorian councils.

They found 1,800 church-owned properties, including churches, presbyteries, schools, nursing homes, hospitals, offices, tennis courts and even mobile phone towers.

But beyond real estate, there was superannuation, telecommunications, Catholic Church Insurance and Catholic Development Funds, which serve as an internal treasury.

Catholics for Renewal's Peter Johnstone, a corporate governance consultant, said most Catholics would have no idea about the extent of the church's assets.

"Certainly there's been no public record available to Catholics," he said.

"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."

Tax-free status 'should be reviewed'

Professor Ann O'Connell, a taxation specialist at Melbourne University's Law School, said the definition of charity should be examined.

And she said the Catholic Church's tax-free status should be reviewed.

What does the Church own? Churches, presbyteries, schools, nursing homes, hospitals, offices, tennis courts, mobile phone towers

Churches, presbyteries, schools, nursing homes, hospitals, offices, tennis courts, mobile phone towers Superannuation, telecommunications, Catholic Church Insurance and Catholic Development Funds

"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 said.

"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."

Professor O'Connell said there was a review underway of the ACNC.

"It would be open to the review panel to find that exemption for basic religious charities no longer can be justified," she said.

"It also tends to discriminate against newer religions, because they become incorporated and then can't take advantage of it.

"So we're really talking about the older established churches not having to account in the way that others do."

Figures don't match up

The reported figures are in stark contrast to those on the public record.

For instance, the Catholic Church told the royal commission it was worth $109 million in Victoria, based largely on historical costs of property rather than market rates.

At the same time, protection of the church's assets has long been cited as a reason to minimise the payouts to sex abuse victims.

But Francis Sullivan from the church's Truth, Justice and Healing Council denied 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."

Mr Sullivan said the Catholic Church had "lots of property", on which they had built hospitals, schools and welfare services.

"So really, we're talking about the actual works of a church now when we're talking about paying survivors for proper redress," he said.

"The church will need to step up and pay, regardless of how you would determine wealth."