People behind it?
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.
"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."
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."