Lord Mandelson said progress on widening access had been limited
Campaigners have welcomed an idea to give poorer students a two grade "head start" to help them get places at the leading universities.
Business Secretary Lord Mandelson is looking at the idea, and a variety of others, to increase social mobility.
Les Ebdon, of university think tank Million+, said it was important to widen the social mix in universities.
However critics said the onus should be on schools to produce better candidates and added that the idea was unfair.
One consequence of the "head start" idea would be middle class students from successful schools being "bumped" from places on popular courses.
In a speech delivered in July, Lord Mandelson said that limited progress had been made in widening access to higher education.
He said there was a strong case for using more contextual benchmarks for talent spotting which look at the way candidates have exploited the opportunities open to them.
Mr Ebdon said: "I think what all universities are in the business of looking for is potential among the students rather than achievement."
However he added that because students from better background achieved more did not mean that they had a higher potential.
Mr Ebdon said the idea to give poorer students a grade boost was "a way of attempting to level the playing field".
He added: "We have a real problem in this country. Our medical schools are full of very earnest young people from middle class backgrounds and then we find it very difficult to find , for example, GPs to go and work in working class areas.
"Therefore we have got to do something to widen the social mix and traditionally medical schools have been seen as the preserve of middle classes rather than appealing across the whole spectrum of people."
Katie Ivens, of the Campaign for Real Education, said the plan was positive discrimination.
She said: "It is not fair on those who study hard , it is not fair on the schools that actually produce a good quality education.
"You cannot just push people into university because they come from a certain background and hope that will solve the problem."
Ms Ivens said the standard of teaching in secondary schools and primary schools also needed to be examined.
She said the plan would create the possibility of a good grammar school student missing out on a university place to a student with worse results who may not make the grade.