A furious independent private school sector has unleashed a last-ditch campaign against planned changes to school funding, warning of "disastrous outcomes", rising fees and a flow-on effect to public schools.
They have also foreshadowed a campaign against the proposed changes that could land Education Minister Simon Birmingham in yet another school funding fight, just as he prepares a possible peace offer with the disgruntled Catholic school system.
In a pointed warning that the government stands to lose the support of the independent sector, the head of the NSW Association of Independent Schools, Geoff Newcombe, told Fairfax Media: "We are not going to accept transfers of money from one system to the other.""We are not going to accept transfers of money from one system to the other," said AISNSW head Geoff Newcombe.
It follows reports last weekend that a shake-up of the funding formula will by throwing out the old socio-economic status model and using parents' tax returns to ascertain their capacity to contribute to the school.
Under various options being considered, Catholic schools would win up to $1.8 billion extra over 10 years, while independent schools would lose up to $2 billion.
The Independent Schools Council of Australia and its NSW and Victorian affiliates have written to the National School Resourcing Board, which is conducting the review, to register their unhappiness about the proposals.
They have also written to hundreds of school principals across NSW and Victoria warning of fee hikes, invasion of privacy and further flight away from private schools - as well as drumming up animosity against their Catholic opponents.
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Dr Newcombe told principals the loss of funding would affect all types of independent schools, "causing fees to rise and limiting school choice for parents".
"There would also be an impact on government schools in NSW which are already struggling to accommodate increasing enrolments," he wrote. "We also understand that other options potentially under consideration would produce similarly disastrous outcomes for the independent sector."
Independent Schools Victoria chief executive Michelle Green told her 220 principals to expect a backlash from parents worried about invasion of privacy if their tax returns were used to calculate school wealth.
And she encouraged principals to spread the word to parents, teachers and MPs, vowing to supply talking points for a lobbying effort that could rival the Catholic sector's relentless campaign against the socio-economic status model and Education Minister Simon Birmingham.
"We are determined to speak up in defence of the interests of parents from all income groups who make significant sacrifices to send their children to independent schools," Ms Green wrote.
Under the current system, a school's socio-economic status score is worked out based on the residential addresses of enrolled students and official statistics. Higher scores mean reduced government funding.
The independent sector represents some of the wealthiest schools in Australia, including Geelong Grammar and the King's School, though it also administers many low-fee independent schools.
The Catholic sector argues it is disadvantaged because parents in wealthy neighbourhoods who send their children to more affordable Catholic schools are counted as rich under the current model.
Catholic educators - particularly in Victoria - have waged war against the Turnbull government over the Gonski 2.0 school funding arrangements and see a change to the socio-economic status model as one avenue of respite.
In his letter to principals, Dr Newcombe warned that capitulating to the Catholic sector would be seen as "reward for the bullying, misrepresentation and personal attacks that have taken place throughout this campaign".
Businessman Michael Chaney's review is due to go to Senator Birmingham by the end of June. In a Senate estimates session last week the minister said he was unfazed by reports of unrest within the Coalition about how he had handled the dispute with the Catholic schools.
"I'm a confident kind of guy," he said.
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