Prime Minister Julia Gillard says the Government will not be releasing its response to the Gonski review of school funding for a number of weeks.

The review recommended an extra $5 billion be spent on schools and found the funding model for public and private schools needs to be overhauled.

The Government's response had been expected this week.

Ms Gillard says school funding must drive better outcomes and higher standards in Australian schools.

"I am worried as Prime Minister that whilst our school reform work is gathering results because our schools were neglected for too long under the former government, [that we] are now slipping behind the education race in our region and in the world," she said.

"That's ultimately bad news for our economy."

Opposition Leader Tony Abbott says the delay is a "disaster" for the Government.

"It's another sign that this Government is both untrustworthy and incompetent," he said at a press conference in western Sydney on Sunday.

He says there will be no certainty about funding for schools until the Government releases its response to the Gonski review.

Mr Abbott says modelling on the review shows one third of Australia's 9,500 schools will be worse off.

"There is a new hit list and one third of Australian schools are on this hit list now," he said.

"It is absolutely imperative that the Prime Minister immediately release the Government's official modelling and until such time as she releases the official modelling, parents can have no certainty that their school's funding is safe."

The Greens also urged the Government not to delay its response.

Greens education spokeswoman Senator Penny Wright says the Government needs to implement the Gonski recommendations as a matter of urgency.

"Gonski is unequivocally clear that we have a broken and unclear funding system in Australia," she said.

"We know that we have a causal link between disadvantage and school performance. We know what is needed - much more investment in schools across the board and particularly those schools where there is great need.

"We need to just get on with it."