A CONSERVATIVE Christian school misused the courts to silence a whistleblower who had accused it of multimillion-dollar Centrelink and tax fraud, State Parliament has heard.

The Greens upper house MP John Kaye used parliamentary privilege to accuse Redeemer Baptist School of seeking to "crucify" its critic, the Parramatta accountant Graham Glossop, in an "appalling attempt to drive him into bankruptcy and jail".

Dr Kaye said Mr Glossop successfully battled an apprehended violence order, a defamation action and allegations of assault levelled by the school or its leaders.

Within days of assault allegations being dismissed, Mr Glossop was served with a court order providing the school's representatives with the right to search premises and seize evidence without warning. The case was withdrawn this year. But Dr Kaye said defending the matter cost Mr Glossop, whose daughter once attended the Parramatta school, and his friends $400,000, and forced him to sell his home, his business and an investment property.

Last year Dr Kaye invoked parliamentary privilege to call for a full state and federal investigation into allegations of tax and welfare fraud. Despite denials of impropriety, he alleged elders of the church running the school accrued a property portfolio worth more than $50 million and put in place "a set of bizarre and deceptive employment arrangements practices" at its school to avoid paying fringe benefits tax.

This week the bursar of Redeemer Baptist School, Russell Bailey, said the allegations of fraud were rubbish and the school was most disappointed that Dr Kaye had again used the protection of parliamentary privilege to make "outlandish and unsubstantiated allegations against the school and its community".

"The school has undergone extensive investigations from a number of Government bodies as a result of false allegations made by various people, including Mr Kaye. Those investigations have found that none of the allegations can be substantiated, and that is simply because they are not true. One of the serious allegations raised by Mr Kaye is that of "sexual assault". This allegation was independently investigated, under supervision of the Ombudsman, in 2005. It also was "not sustained".

Mr Bailey referred to a letter written by Mr Glossop as part of the latest legal settlement, saying he was happy to end litigation and wished the school the best.

But in Parliament, Dr Kaye said he estimated the school had spent more than $2 million in pursuit of Mr Glossop. "Redeemer Baptist School has misused the courts in a barbaric attempt to destroy Mr Glossop for no other reason than that he had the courage to speak the truth. Their efforts to silence Mr Glossop have served only to highlight the very things they wish to hide: their ongoing tax fraud and their ongoing Centrelink fraud."

The church broke away from the mainstream Baptist Church in 1974, and the Baptist Church has reaffirmed it has no association with the school, founded in 1981.