The books of Australia's wealthiest church organisation, the Catholic Archdiocese of Sydney, have been made public for the first time. And according to what the child sex abuse royal commission heard on Tuesday, the Archdiocese has $1.24 billion worth of assets, plus annual multimillion-dollar surpluses.

All these, according to Danny Casey, the archdiocese's business manager, are "ultimately controlled by - owned by, if you like - the archbishop of the day."

Between 2004 and 2007, Mr Casey told the commission the Sydney archdiocese earned surpluses of between $7.7 million and $44 million. It has cash reserves amounting to $320 million alone. Annually, the church has been earning up to $43 million a year since 2001, the year George Pell was appointed as archbishop.

Victims of sexual abuse by priests of the Sydney archdiocese receive payments from a $426 million "procuration fund," one of two funds that control the money. The other is the Catholic Development Fund which has gross assets of $810 million, including $321 million in cash at the end of 2013.

According to Mr Casey, the church made a "very, very bad decision" when it refused to settle the $100,000 pre-litigation settlement asked by sex abuse victim John Ellis in 20014. The case ended with the Archdiocese shelling out $1.5 million, including $568,000 in ex gratia payments to Mr Ellis.

"What you are indicating, as I understand it, is that in many years the church makes significant investments - but from property transactions and other transactions gets significant returns, is that right?" Justice Peter McClellan, chairman of the royal commission, asked Mr Casey.

"That's correct," Mr Casey replied.

"No doubt your prudence in this is commended, but in many years, there are significant amounts of money that provide significant returns?" Mr McClellan asked.

"That's right, your honour", Mr Casey replied.

Mr McClellan was aghast over what he heard. "To a lawyer, it sounds like a bank."