University staff have rejected any move to introduce two-year degrees, warning they would lead to "academic sweatshops" and affect standards.
The University and College Union said plans for "fast-track" degrees would damage the reputation of UK degrees.
The union's annual conference, which is meeting in Manchester, voted against their introduction.
Delegates said they would massively increase workloads and reduce time they could spend on research.
They said squeezing three-year degrees into two years could not be achieved on the back of "swingeing cuts" to higher education and would have a "devastating impact" on the quality of students' experiences.
Karen Evans, from the University of Liverpool, said: "Accelerated degrees have no educational value and will stop students from having a well-rounded education.
"As well as placing a huge strain on staff it will also mean an additional burden on students, many of whom have to work through the summer to pay back the debts of tuition fees."
The union's general secretary, Sally Hunt, said: "Two-year degrees may sound great on paper but are in effect education on the cheap.
"They would be incredibly teacher-intensive and would stop staff from carrying out vital research and pastoral duties.
"Our universities are places of learning not academic sweatshops and we need to get away from the idea that more can be delivered for less.
"Cuts, such as the savage ones currently planned, will have consequences.
"I fail to see the logic of piling 'em high and teaching 'em cheap in a two-tier system designed purely to mask the failings of the government to properly fund higher education."