Australia could go to the polls twice before families know the makeup of the new national funding model for schools, after the Federal Government's latest policy delay, according to Greens Senator Sarah Hanson-Young.

Senator Hanson-Young, Greens spokesperson on Education, says the extension of the Government's school funding model for another 12 months will disappoint many schools, parents and communities, as it keeps in place a system the Greens believe is flawed and inequitable.

"Just like the Government's move to push a decision on an ETS back to 2013 has delayed action on climate change, today's announcement adds yet another year to the growing delay in tackling inequities in Australia's school funding system,'' Senator Hanson-Young said.

"The reality is that this is still John Howard's policy on schools funding. Labor said it was flawed, but now it is backtracking.

"Julia Gillard seems to be taking up the Kevin Rudd approach of all review, no leadership.''

The Greens know the funding review is already long overdue - research by Dr Jim McMorrow has found that there is an estimated $12 billion shortfall in Commonwealth funding between the public and private school system over the forward estimates. That is before the announcement of the 12-month extension of the funding model.

"The new policy maintains the current funding model until 2013, meaning that the earliest chance for any effective change is 2014, more than two elections after Labor took office,'' Senator Hanson-Young said.

"Under the existing figures, by the end of 2012, public schools will still only receive just over a third of the available money despite providing education to more than two-thirds of our children.

"The reality is simple - the Government must put more funding into public schools to narrow the funding gap.''