The Abbott Government is facing claims its offer to WA on schools funding short-changes the State by almost $60 million.
Under an arrangement hurriedly struck by Education Minister Christopher Pyne this week, WA would get $120 million over the next four years.
Mr Pyne and Prime Minister Tony Abbott indicated this amount reflected the revised amount offered by then prime minister Julia Gillard to Premier Colin Barnett in June.
But Federal figures from June show that WA was actually offered $178 million in Federal funding for 2014-18, or 65 per cent of a total funding package of $273 million that assumed a State contribution.
Perth Labor MP Alannah MacTiernan said that even on the "most generous analysis", WA was being offered $58 million less than offered by the Gillard-Rudd government.
"But it's not just about the quantum, the targeting of funds to where they are needed most - which is the essence of the Gonski reform - has been abandoned," she said.
"How are we going to get better outcomes by just doing the same old thing? The minister rants about the education standards - as do I - but says it is up to the States to set the standards and he will not intervene."
Mr Barnett yesterday conceded that WA would get less under Mr Pyne's offer than under Labor but said the difference was $17 million.
He said the advantages of the coalition offer was that WA would get more money in the first year and that the money would be given without handing control to Canberra.