Students would apply electronically for university places after receiving their A-level results, under plans put forward this week by a working party of teachers and academics.
Currently, applications have to be in by December and teachers predict students' grades nine months in advance of their exams.
John Dunford, general secretary of the Secondary Heads Association, said:
"We believe this system would be fairer to our students. Decisions are made on the basis of predicted grades, and they are notoriously unreliable.
"I'm pessimistic that we shall achieve a post-qualification system in the foreseeable future. The universities don't want change because the present system appears to them to be working."
Professor Brian Smith, who chaired the group and is vice-chancellor of University College Cardiff, agreed that predicted grades were not very accurate.
"But the system does deliver the right numbers of students in the right subjects," he said.
The exam boards - which would have to deliver A-level results three weeks earlier under the proposed system - are also taking a cautious approach to changes.
But UCAS, the agency which manages the applications process, is backing the proposals. It already receives around 30-40,000 applications electronically, and can turn them around in three days.