Academics will be invited to have their say on plans for post-qualification applications (PQA) later this month.
The Universities and Colleges Admissions Service will open a consultation on admission reforms on 31 October, which will run until January, with a report to be published in March 2012.
Plans for a system in which students apply to universities after they have received their exam grades, rather than using predicted marks, were unveiled by Mary Curnock Cook, chief executive of Ucas, at a private meeting with vice-chancellors in London last month.
Such a system would require teenagers to sit their A levels a month or six weeks earlier, and receive their results in July rather than August, allowing enough time for interviews and selection. Other reforms will also be put forward by Ucas - which processed almost 695,000 applications in 2011 - to help it reduce its bureaucracy.
David Willetts, the universities and science minister, expressed support for PQA earlier this year and is reported to be interested in the latest proposals. But some of the most selective universities have expressed misgivings about shortening the time available to assess students.
Wendy Piatt, director general of the Russell Group of large, research-intensive universities, said fears that predicted grades discriminated against students from poorer families were unfounded.
"PQA would do nothing to address the fundamental issue of inequality of attainment at school, which largely determines access to highly selective universities," she said.
Criticism of the "unfairness" of a system based on predicted grades, of which almost half were wrong, were also overstated, she claimed.
Dr Piatt said that almost 90 per cent of predictions were accurate to within one grade. Overall, 53 per cent were spot on, 40 per cent were over-predictions and just 7 per cent under-predictions.
"Students from lower socio-economic groups are more likely to be over- not under-predicted," she added.
Terry Hoad, president of the University and College Union, argued that PQA was "fairer" than the current system, but raised concerns about how the altered admissions timetable would affect teachers and academics.
"We cannot expect our colleagues in schools to curtail the time they have with their students to bring them up to a high level," he said.
"Equally, we do not want our academic members tied up during the summer with admissions - not because they need long holidays but because it's the main period they have to do research."
Matthew Andrews, chairman of the admissions group of the Academic Registrars Council, said a "hybrid" system of PQA and the existing system might work best.
A system using pre-exam applications resulting in "expressions of interest" that gave "greater weight to grades achieved" could be a better model, he said.
Different application timetables for the universities of Oxford and Cambridge, medicine and dentistry could also be reassessed, he suggested. "It creates a mystique that can put some people off. We need to ask why they have these rules and what they are adding."