Students' unions have been taking sides for and against the ongoing industrial action by university lecturers.
The AUT action has angered many students
Twenty-one students' unions from across England said the assessment boycott undermined years of close relations between staff and students.
But the National Union of Students maintains that the majority of its campus members support the action, taken as part of a pay dispute.
And more than 30 have signed a counter-protest, backing the boycott.
The tensions are the product of an ongoing dispute involving members of the Association of University Teachers (AUT) and the other main lecturers' union, Natfhe.
The unions have rejected as "derisory" an offer by the University and Colleges Employers Association (UCEA) of 3% from August this year and an extra 3% from August 2007.
Lecturers have been refusing to mark work or take part in appraisals and now, with the exam season fast approaching, the prospect of final-year students not being able to graduate this summer is becoming more and more likely.
The AUT is boycotting the setting and marking of exams, while Natfhe is boycotting just the marking of exam papers.
The unions and employers met on Friday under the auspices of the conciliation service Acas and agreed to meet again next week.
Representatives from 21 student unions wrote to the AUT general secretary, Sally Hunt, and to the NUS to complain about the action.
The letter is supportive of lecturers' claims for better pay: "We believe academics have been underpaid for too long."
But it condemns the current approach of the unions.
"We cannot support an action which both creates undue stress for them [our members] during this vital time of year and potentially threatens them with the possibility of not graduating at the end of the year," the letter says.
"We urge you to reconsider your position and hope that you will recognise that alienating student support will have a significant impact on how future generations of students see their relationship with their lecturers."
Alain Desmier, president of Exeter University's Students' Guild, said the high pay rises being sought by the AUT could backfire on students, forcing universities to raise tuition fees from £3,000 a year to £5,000.
"The NUS hasn't thought about this - it hasn't intellectually looked at the AUT's proposals," he told BBC News.
Kat Fletcher, president of the NUS, said the union was happy to debate the issues surrounding the strike with individual students' unions.
"However, NUS shares concerns about the impact of the industrial action on students particularly with the exam season looming," said Ms Fletcher.
"Whilst we can't stop the action of the teaching unions, who are following a course of action voted for by their members, we will continue to extensively lobby the teaching unions on a variety of issues and concerns," she said.
Those included the AUT's decision not to set exams which would mean that restoring a normal service to students would take longer once the dispute was settled.
Following media reports of the letter opposing the industrial action, the president of Warwick University Students' Union, Kat Stark, drafted another to the AUT's Sally Hunt.
It had been signed by 32 student union presidents within a day, she told her.
"I continue to hear from more students' unions who want to join forces to reiterate our full support for the industrial action taken by the AUT at the moment," said Ms Stark - who is also the NUS national women's officer-elect.
Her letter says: "Our lecturers have been underpaid and overworked for decades, which has had a massive impact on the quality of our education.
"We don't want to be taught by lecturers who are poorly paid and working hours and hours of unpaid overtime."
It says vice-chancellors had given them no option but to take action as a last resort.
"And contrary to the impression put forward by newspaper reports ... this is the overwhelming feeling amongst students," it adds.
The issue has caused splits within students' unions as well as between them.
It has been claimed that the officers of some students' unions backed the protest letter, even though their members had voted otherwise.