The Turnbull government has been accused of misleading parents about the impact of its Gonski 2.0 school funding changes by using "fantasy" figures in its online funding estimator.
The Catholic sector is particularly furious about the highly-publicised funding estimator, which it claims has disguised substantial funding cuts to many of its schools.
Government MPs have been referring concerned parents to the School Funding Estimator website, which provides federal government funding estimates for each school in the country for this year, next year and 2027.
Education Department officials confirmed at Senate estimates hearings on Thursday that the 2017 estimates on the website do not reflect what schools have actually been allocated by the federal government this year.
This year's estimates are instead calculated using the proposed new funding formula, which would not take effect until 2018.
Labor senator Jacinta Collins described the figures in the funding estimator as "completely illusory" and "inaccurate".
"These figures are based on a reality that will never exist," Senator Collins said.
"They are based on a fantasy."
For example, the funding estimator says St Dominic's School in Camberwell East received a federal government funding allocation of $756,600 this year, which would grow to $783,800 in 2018.
St Dominic's was actually allocated $1.92 million this year under the current formula, meaning its federal allocation would plummet by $1.14 million next year.
The funding estimator says Sacred Heart Catholic Primary School in Pymble received a federal funding allocation of $624,633 this year, which would rise to $648,550 in 2018.
Sacred Heart was actually allocated $1.76 million this year under the current funding formula, meaning its federal allocation would drop by $1.1 million.
National Catholic Education Commission acting executive director Danielle Cronin said the actual 2017 allocations and the figures published on the website "bear no resemblance to one another".
"For some reason, the minister [Simon Birmingham] has felt the need to recalculate the 2017 allocations to create the impression that all systemic Catholic schools will see their funding allocation grow in 2018," she said.
"We know that's not the case for 40 per cent of our schools.
"The minister is confusing and misleading parents and principals."
Education Minister Simon Birmingham said the website reflected the fact total funding for Catholic schools will increase by 3.7 per cent annually over the next four years.
He stressed the website did not reflect the funding schools actually receive because Catholic and state authorities distribute funding among their schools as they see fit.
The inquiry also heard that the 24 "over-funded" private schools that are set to have their funding cut next year would continue to surge if the government's changes are blocked.
Fairfax Media understands the mostly high-fee private schools on Sydney's north shore would receive an extra $322 million over the next decade if the current legislation remains in place.
Elite all-girls school Loreto Kirribilli - whose funding would fall by $13.8 million over the next decade under the government's changes - would see its funding rise by $12 million over 10 years under the current legislation, for example.
This means Loreto Kirribilli would receive a windfall of $25 million over the decade if the government's changes are voted down.
The Senate hearings also heard that public schools in NSW and Victoria would remain under-funded after a decade under the new model unless state governments substantially increase their funding.
If state governments maintained their current funding levels, NSW public schools would be funded at 91 per cent of the Schooling Resource Standard on average by 2027.
The Victorian public school sector would be funded at 86 per cent of the SRS by 2027 if the state government maintained current funding levels.
Photo: James Hall
Senator Birmingham, above, said more pressure should be applied to state governments to boost funding to their public schools.
A Senate committee examining the government's proposed funding model has not invited state education authorities to give evidence despite the fact they own and operate public schools.
Victorian education Minister James Merlino said: "It's incredible that the states and territories - who run the vast bulk of Australian schools - haven't been invited to give evidence at these hearings.
"It's typical of Simon Birmingham's attitude - ignoring Victoria while he slashes funding to our schools."
Labor education spokeswoman Tanya Plibersek said: "By banning state and territory governments from appearing before this inquiry, Malcolm Turnbull is shutting out every public school in the country.
- with Henrietta Cook
