State governments are only guaranteed less than 20 per cent of the funding they stood to gain under a schools deal that has been ripped up by the Abbott government, the Australian Education Union says.

The federal government said this week it would honour only one year of the school funding model, and allocate $230 million in 2014 to states that did not sign up to the scheme.

While the government insists it will maintain the same amount of funding for schools over the next four years that Labor had put forward, states that signed up to Gonski fear the new model federal Education Minister Christopher Pyne will unveil next year will strip money from public schools and direct it to the independent sector.

Mr Pyne has committed to maintaining a ''sector-blind'' approach to funding - treating government and independent schools the same - only in terms of the extra money that disadvantaged children attract. These loadings comprised 17 per cent of Labor's additional funding package, putting the rest of the previously promised money in doubt, the union says.

Australian Education Union deputy president Correna Haythorpe said: ''By only committing to deliver around one-fifth of the money on a sector-blind basis, Mr Pyne is clearly signalling he wants to maintain the inequity of the current arrangements and cut the share of money going to public schools.''

However, Prime Minister Tony Abbott insisted on Saturday his government had not broken an election promise to maintain the same amount of funding for schools over the next four years that Labor had put forward.

''This is a government which always keep its commitments,'' he said.

In a statement, Mr Pyne added: ''This is the kind of hysterical fear-mongering we've come to expect from the Australian Education Union.''

With AAP