Christopher Pyne’s pledge to go back to the drawing board on schools funding reforms has states worried about the future of their agreements.

States are demanding the Abbott government stand by its pledge to honour Labor’s schools funding agreements after Education Minister Christopher Pyne flagged a revamp of the reforms.

Mr Pyne accused the former federal government of leaving the so-called Gonski reforms in a “shambles”, saying deals had not been finalised with the Catholic education sector, nor with the Victorian or Tasmanian governments, as claimed at the time.

Despite pledging before the election to honour Labor’s Better Schools plan, Mr Pyne said he would have to go back to the “drawing board” to reconsider how the funding model is delivered.

The change of heart sparked concerns from states, with Tasmanian Education Minister Nick McKim saying the Abbott government must commit itself to the agreed schools funding deals.

“The Tasmanian government signed a binding heads of agreement with the former commonwealth government, and submitted our implementation plan,” he said.

“We expect the new federal government to honour its election promise and uphold the Better Schools agreement.”

A Victorian government spokesperson said Mr Abbott had promised to honour the agreement struck on schools funding in August.

“Victoria made it clear that, along with Victorian schools and school communities, we expect the Commonwealth to honour this funding,” they said in a statement.

NSW Education Minister Adrian Piccoli said the state had a “binding agreement” and expected it fulfilled.

“We have already implemented the new funding model to NSW’s 2200 schools, and it has been received with wide acclaim from the education sector,” Mr Piccoli said in a statement.

“Any attempt to change the model now may see both government and non-government schools lose funding.”

Federal opposition leader Bill Shorten said the government was using “weasel words” to wriggle out of the agreements it had pledged to support.

“Before the election the government said it is not an issue, it’s a unity ticket, no daylight between Liberal and Labor,” said Mr Shorten, who was education minister in the former Rudd government.

“Now we see the coalition government saying `Well, actually we don’t mean what we said then’.”

The Catholic schools sector was supportive of the review, despite backing the Labor reforms.

Independent Schools Queensland urged Mr Pyne to improve the funding model to “ensure less complexity and more stability”.

The Australian Education Union said the government was breaking an election promise to maintain the Gonski reforms.

“Minister Pyne should be focused on making sure these reforms apply to each and every state and territory,” federal president Angelo Gavrielatos said in a statement.