Wealthy families are turning away from elite private schools, new figures show.
In 2006, just over 40 per cent of students from high-income families were enrolled in government schools. Enrolments in government schools have increased proportionally by almost 7 per cent since then, equivalent to tens of thousands of families, according to figures obtained for Fairfax Media by the Australian Bureau of Statistics.
In Victoria, there are now proportionally 12 per cent fewer children in independent schools compared to a decade ago, with an extra 4 per cent of families heading to the Catholic sector, and 8 per cent to government schools.
In NSW, 50 per cent of all families earning over $156,000 a year are now sending their kids to public schools, compared to 43.6 per cent a decade ago. While 27.8 per cent now attend Catholic schools and 22 per cent go to private schools, down from 29 per cent in 2006.
"The figures challenge the myth that independent schools are the sole preserve of the wealthy," said Independent Schools Victoria chief executive Michelle Green. "In fact more than half of the students at independent schools are from low and middle income families."
The pattern is replicated across the country and is set to heap pressure on already-stretched state public school systems that have been forced to install demountable classrooms by the hundreds in order to meet demand.
Former KPMG partner Timothy Norris sent his son to independent schools in the United States, Brazil and Australia before moving him into the state school system in Year 8 at Albert Park College.
"My son has blossomed," he said. "He has taken on three different instruments and mastered them."
The change has saved the family $25,000 a year, although Mr Norris said this was not a factor in the move. "It's a pleasant benefit," he said.
The data, taken from the 2016 Census, comes as the school funding debate pushes its way back into Parliament this week.
In a new set of responses to questions on notice from Greens Senator Sarah Hanson-Young, the Department of Education has advised that more than 120 NSW Catholic schools and 123 Victorian Catholic schools are currently over-funded, while 241 independent schools are over funded nationwide.
More than 600 NSW public schools and 195 Victorian public schools have also exceeded their resourcing standard, according to the document.
Tensions between the sectors are now spilling over into accusations of misleading research and name-calling, as Education Minister Simon Birmingham's National School Resourcing Board meets in Canberra on Thursday to begin talks on how the socio-economic status of each school will be calculated in future.
Lobbying of government backbenchers has been ramping up in the past week with principals in the Catholic sector calling Coalition MPs to heap pressure on them to change the government's line on its Gonski 2.0 reforms - which they say will cost their schools millions of dollars a year and could force up to 50 to close.
But new MySchool modelling by the Independent Schools Council of Australia shows that Catholic schools in the median socio-economic range [101-115] are receiving up to $2000 more per student per year in NSW and Victoria compared to independent schools, while those that have been given a high socio-economic [121+] rating are receiving almost double the level of government funding.
The Catholic sector now says the entire socio economic calculation system is broken and based on flawed Australian Bureau of Statistics data, which places greater focus on the status of the suburb the school is located in than the circumstances of individual families.
The Catholic system pools funding for its schools and then distributes it based on its own methodology and has fiercely defended its right to do so amid efforts to bring it into line with the public and independent systems, where funding is distributed by the government on a school-by-school basis.
"The Coalition has eroded the ability of the Catholic church, and other denominations who also aim to run quality, accessible, inclusive schools to by putting an end to the tool that facilitates funding being spread across all schools to meet their special needs," a spokesman said.
Education Minister Simon Birmingham fired back on Sunday.
"Our plan ends the situation where if you changed the sign on a gate from being a Catholic school to another type of non-government school the amount of money the government would deliver would drop," he said.
"Rather than lobbyists trying to return Australia to the model that saw special deals take precedence over the needs of students in the way schools funding was distributed, I'd encourage those people to focus on working constructively and collaboratively with the board so we can boost education outcomes for all students."