Parents who help to set up free schools could be given guaranteed places for their children under reforms to the admissions code being considered by ministers.
If implemented, the move is likely to be seen as a U-turn by the Government as both officials and ministers have previously said that free schools will have to abide by the admissions code in the same way as other state schools.
Union leaders and campaign groups today warned that such a change could lead to middle-class parents setting up schools so their child does not have to mix with "the great unwashed."
A spokesman for the Department for Education said the proposals were at an early stage, but added that ministers feel it is "right and common sense that people who invest a lot of time in setting up a school should have priority for their children."
He added: "There are no decisions yet - but we've been looking carefully at the mechanics of how this would work - who it would apply to, when it would start, the effect on small schools."
But Dr Mary Bousted, general secretary of the Association of Teachers and Lecturers (ATL) told the Times Educational Supplement, who first reported the proposal, that the move "makes a mockery" of Education Secretary Michael Gove's claim that free schools will be for everybody.
"It completely paves the way for pushy, middle-class parents to set up a school so their children don't have to go to the same school as the great unwashed," she said.
"It makes a mockery of the idea that free schools are for all. They are not for everybody - we know they are disproportionately in the less deprived communities, where these schools are not needed."
Author and journalist Toby Young, who is the first to have been granted approval to open a free school, the West London Free School, in September, has said that without changes to the admissions rules his own children may not get a place.
"If they do change it, it will be politically contentious," Mr Young told the TES.
"But I don't think members of the public would think it unfair unless the numbers were particularly high."
Under the admissions code, schools cannot choose their pupils, but have to adhere to strict guidelines, designed to given every child a fair chance of a place. It was understood that this would apply to free schools as well.
Information on free schools, published on the DfE's website says: "Like academies, free schools will be bound by the same admissions code that governs all publicly funded schools. Each free school will need to have a fair and transparent admission policy, and will need to provide places for pupils of different abilities who are wholly or mainly drawn from the area in which the school is situated."
Free schools will not be allowed to be selective, it adds.
In response to an urgent question on free schools last June, Mr Gove said: "I intend to ensure that all free schools and all academies continue to abide by the existing admissions code, that all schools that are currently comprehensive remain comprehensive, and that schools are as inclusive as possible."
Ministers have already revealed plans for a slimmed down, simpler admissions code, and it is expected that a consultation on the reforms will be launched within the next few weeks.