Under current coalition plans part-time students would have to start paying back loans three-and-a-half years after starting courses, provided they were earning over £21,000.
This would apply even if part-time students had not yet completed their studies.
The Lib Dem motion – which was overwhelmingly supported by delegates at the conference in Birmingham yesterday - calls on the government to “review” the plans as they treat part-time students differently from their full-time counterparts.
Tom Wood, chair of Liberal Youth, said the current plans were “patently absurd” given the new system was supposed to ensure students did not pay any fees before they graduate.
Belinda Brooks-Gordon, an academic and Lib Dem county councillor who brought the motion, said the proposals were a “glaring inequity” among changes that had in general brought parity for part-time students.
Dr Brooks-Gordon, reader in psychology and social policy at Birkbeck, University of London, told the conference: “Many students, like the ones I teach, will be badly affected if we don’t get this right now.”
Although the main motion was carried with few voting against, a more strongly-worded amendment brought by Liberal Youth, that would have asked for an immediate change, was defeated.
Meanwhile, Vince Cable, the business secretary, chose not to focus on the government’s higher education policy in his speech today to the conference.
His address instead drew attention to excessive executive pay, although he did trumpet the ring fencing of the science budget and work on apprenticeships as achievements.
On apprenticeships, he said the coalition had worked to give “respect and recognition to the 60 per cent of young people who do not pursue academic study in universities”.