Claire Callender, professor of higher education policy at the Institute of Education and Birkbeck, University of London, said that the £143 million-a-year widening-participation premium provided by the Higher Education Funding Council for England may be at risk following the changes to teaching funding.
Speaking in a panel discussion at the British Educational Research Association's annual conference at the IoE last week, she said: "My guess is the Hefce widening-participation premium will go ... All costs of widening participation will land in the lap of higher education institutions."
The possible removal of the premium was one of several policy changes that would "widen inequality in the higher education sector", Professor Callender claimed.
Post-1992 institutions would be hardest hit by any reduction to the premium, which reflects the higher costs associated with teaching part-time students or those from poorer backgrounds.
The more selective research-intensive universities receive less from the premium. The University of Oxford was awarded just under £400,000 last year, the University of Cambridge £419,000 and the London School of Economics £97,500.
From September 2012, efforts to widen participation will be largely funded by individual institutions under agreements struck with the Office for Fair Access.
Universities have agreed to allocate a proportion of their tuition-fee income above £6,000 to fund the work, averaging around £800 for a typical £9,000 fee.
However, Les Ebdon, chair of the Million+ group of new universities, said the premium was still "a key component of the social-mobility agenda because it acknowledges the additional costs of ensuring that students from under-represented groups not only enter higher education but are also supported while studying".
He added: "Suggestions that widening-participation funding is no longer important or should be merged into the teaching grant are damaging because the endgame would be abolition. This would undermine the political importance of social mobility and also ignore the practical and financial implications of delivering it in higher education. It would also be unwise in a time of heightened social division."
Professor Callender's warning follows the end of a consultation by Hefce on how the remaining £2 billion teaching grant should be spent once state support is slashed by 40 per cent (£2.9 billion), cuts that will be fully in place by 2014-15.
The Russell Group and 1994 Group of research-intensive institutions have called for the cash to be concentrated on high-cost courses such as science, medicine and engineering, arguing that their costs are not covered by £9,000 tuition fees and proposed subsidies.
Neither group commented on the future of the premium.
However, a Hefce spokesman said: "The priority is to recognise that there are additional costs associated with this activity.
"We will be consulting in 2012...on more detailed proposals for the allocation from 2012-14. We envisage that the allocation for widening access and improving provision for disabled students will continue along similar lines as at present."