Council leaders have been asked to agree the plan
The Scottish government has offered councils a deal on speeding up its drive to cut class sizes through the scaling back of free school meals.
The SNP, which has been under fire over the issue, insisted cutting class sizes was vital, but had to be paid for amid the current public spending squeeze.
Ministers said the offer would deliver maximum P1-P3 class sizes of 18 by August 2010 for 11,000 extra pupils.
Opposition parties said the move had humiliated the Holyrood government.
The SNP has been under sustained opposition criticism over whether its manifesto pledge to cap pupil numbers at 18 in the first three years of primary education would ever be delivered.
The policy formed part of the Scottish government's concordat with the 32 councils, but when ministers said in September they would bring in legislation to cap numbers at 25 pupils and only in P1, rival parties claimed it had been ditched.
Mike Russell, who last week replaced Fiona Hyslop as education secretary, said the new offer had been discussed with the council body Cosla, and would be put to the leaders of Scotland's local authorities.
In return for speeding up class size reductions, the Scottish government said it would give councils "the flexibility to prioritise free school meals for children in the most deprived areas", as part of progress towards universal free school meals.
Scottish Labour leader Iain Gray said the offer meant two manifesto commitments had now been ripped up.
"This is a damning admission by the SNP of their failure to deliver the big promises they made," he said, adding: "Alex Salmond has ripped up his manifesto and the concordat in one fell swoop. He has admitted defeat."
Tavish Scott, the Scottish Liberal Democrat leader, said: "Mike Russell's first act as education secretary has been to run up the white flag on every SNP education promise.
"This is a humiliating U-turn for the SNP."
Conservative schools spokeswoman Liz Smith added: "The SNP should admit that the game is up. It can apply all the sticking plasters it likes to its broken education pledges, but until Alex Salmond and the SNP wake up to the real issues nothing will get better.
Mike Russell said cutting class sizes was a priority
"The historic concordat has now been consigned to history."
Mr Russell said the recession was putting substantial pressure on public finances and a clear proposal was needed for the way forward.
"The Scottish government, in partnership with Cosla, is firmly committed to the reduction in P1 to P3 class sizes," he said.
"I firmly believe delivering smaller class sizes in P1 to P3 is a necessary step towards improved attainment.
"Evidence and common sense tell us that more quality time with teachers pays dividends, particularly for the most vulnerable children."
On the councils, the education secretary added: "We are determined the strength of our relationship will be demonstrated by the way in which we take forward this issue."
Outlining the offer, Scottish ministers also suggested an alternative way of approaching targets on expanding pre-school provision, while stressing that Westminster had its part to play in helping boost recognition for "kinship carers" who look after children.
Scottish councils will be asked to outline how far they can go towards the class size target under the offer, before further talks are held on the way forward.