Analysis by Fairfax Media shows that if Catholic schools were to start from the same position as independent schools, they would be $1 billion worse off over the decade. If they were to start from the equivalent position of public schools, they would be $2.3 billion worse off. Education Minister Simon Birmingham - who hammered Labor leader Bill Shorten for brokering "special deals" while education minister under Julia Gillard - conceded his Gonski 2.0 model temporarily preserved some special deals because they would take six to 10 years to "phase out". He accused Labor of trying to "see how many votes they can buy" by pledging even more money to Catholic schools, and fanned the flames by likening Catholic educators in Victoria to Judas, suggesting they were "bought by a few pieces of silver" from Labor. He refused to apologise on Tuesday, despite pressure from senior Labor ministers and anonymous critics in the Coalition. Education Minister Simon Birmingham Credit:Alex Ellinghausen The National Catholic Education Commission does not accept it is in a privileged position. Acting executive director Ray Collins dismissed that as a "retrospective argument", while Nicola Taylor, the group's senior data and policy analyst, said "flaws in the system in the past" did not justify "flaws in the system in the present".

Instead, the Catholic sector says it is being robbed to the tune of $1.1 billion, because overfunded schools within its system had their money cut straight away - rather than over 10 years, like independent schools. "They went from being overfunded to underfunded virtually overnight," Ms Taylor said. She gave the "extreme example" of an unnamed Catholic school in Sydney that was receiving 130 per cent of its appropriate allocation, which she said "lost $3.7 million of its funding in one year". The National Catholic Education Commission does not believe its schools are better off than others. Credit:Reuters The NCEC conceded Catholic educators in each state or diocese ultimately decide how much money each school receives, not the Turnbull government. However, Senator Birmingham has also written to each school telling it how much money it should get from head office, effectively tying the Catholic administrators' hands. Jim Hanna, head of external relations at Catholic Schools NSW, stressed the Catholic system as a whole was underfunded, and said he believed the unfair transition process was an "inadvertent mistake" by Senator Birmingham. "The government has been trying to find a way of justifying it ever since," he said.

The anger is most pronounced in Victoria, where Catholic Education Melbourne commissioned robocalls advocating a vote for Labor in last weekend's Batman byelection. Labor has promised to give an extra $17 billion to schools over 10 years, including $250 million for Catholics in its first two years. Loading Jumping into the sectarian war, Labor's education spokeswoman Tanya Plibersek accused Senator Birmingham of making an anti-Catholic "slur" under pressure. "He should apologise," she said. Stephen Elder, executive director of Catholic Education Melbourne, has accused the minister of "sneering", but said he was not offended by the comparison to Judas. He also confirmed CEM had paid for the robocalls in Batman. Despite fears the Catholics will unleash a war chest against the Coalition come the election, the NCEC and Catholic Schools NSW indicated they were unlikely to replicate the robocalls of their Victorian branch. However, they stressed they would clearly inform parents of the parties' school funding policies ahead of the election.