CANBERRA, May 18 - But briefing documents for the meeting show the Commonwealth and states won't sign a new agreement on school reforms for at least another year.

The Turnbull government has outlined a plan to put $18.6 billion more into education over the next decade while moving all schools to consistent, needs-based funding.

State and territory ministers will get the chance to quiz federal Education Minister Simon Birmingham on Thursday.

It's likely to be a heated meeting, with those states who signed six-year agreements with the previous Labor government unhappy at missing out on the extra money attached.

Labor education spokeswoman Tanya Plibersek says the Commonwealth doesn't have the right to "unilaterally junk" those deals.

Legislation for the new plan requires states to sign up to a national education reform agreement to get the federal money.

The briefing to ministers for Thursday's meeting proposes they "provide advice to COAG on funding and reform principles to guide collaborative work that will drive improved student outcomes and position First Ministers to enter into a new national agreement on schooling by June 2018".

It says the new agreement will incorporate recommendations from the new review by businessman David Gonski - who led the original school funding review in 2011 - on the best ways to spend money to improve student achievements.

Gonski isn't due to report until the end of 2017.

Premiers and the prime minister resolved at their COAG meeting in December to have "a specific focus on education reform and funding in 2017, with schools funding arrangements agreed in early 2017".

The new approach taken by the federal government, to change commonwealth funding arrangements only, likely means it doesn't need agreement from the premiers on funding.

But it will need a national agreement to achieve reforms it wants, such as teacher quality checks and earlier testing of students.

Plibersek said not having a new national agreement until mid-2018 left things a "complete shambles".

Meanwhile, Senator Birmingham is calling on the union to drop its I Give A Gonski "scare campaign" given Gonski has backed the government's approach.

It appears more than 2000 people have withdrawn support from a petition on the I Give A Gonski website over the past fortnight - although there were still nearly 175,000 signatories late on Wednesday.

"Hardworking teachers are more interested in results than in playing politics and, increasingly, they are turning their backs on tired old union scare campaigns," Senator Birmingham said.

"I'm committed to ending the school funding wars and the unnecessary partisan politics that some want to infect our schools with."