Growing numbers of students in England have pledged to withhold rent on university accommodation they cannot use during the Covid lockdown.
Organisers say this is building up to be a major protest, estimating that about 15,000 students at dozens of universities have signed up so far.
They want a rebate on rent when many students are being kept off campus at the start of term.
But universities say they only provide 20% of student accommodation.
Universities UK says this means "many decisions on refunds will be made by private landlords and other providers".
In November, University of Manchester offered a 30% rent rebate for the first half of the academic year, worth about £1,000 to each student in halls.
The move followed protests over lack of support during the coronavirus pandemic which saw students tear down temporary fencing in one demonstration.
The reduction will be applied to direct debit payments this month, with students who have already paid for the whole year getting a refund.
But organiser of the Rent Strike Now campaign, Ben McGowan, said the new lockdown means students are still paying for halls they are unable to return to which has prompted a wave of student anger.
On Twitter, campaigners listed more than 40 universities where they said students were pledging to withhold rent.
"Most of us are being told not to go back so we're paying for accommodation we can't use and there's been no extra support from universities and government," added Saranya Thambiranjah, a first year at Bristol University who also helps run the campaign.
"Rent striking is a great way to make our voices heard and get universities to listen our concerns."
Students at universities not yet part of this campaign have said they will organise similar challenges on their own campuses, including Coventry and Keele.
At Nottingham Trent University, student campaigner Rebecca Hyde, who is doing a masters in broadcast journalism, said 244 students had so far pledged to withhold rent on university halls since their campaign was launched a few days ago.
She believes universities should do more to help students who are having to pay for rooms they are unable to use through no fault of their own.
She says her course leaders have been brilliant but missing out on using studios and running "news days" with her fellow students "is just so disappointing".
Nottingham Trent University says it understands student concerns over rents and urged the government "to show leadership to find a solution that is fair to all students".
"At NTU, only a minority of our students are in accommodation operated by or on behalf of the university.
"We do not want a repeat of the situation in the summer term of 2020 where most of our students were reliant on the goodwill of private accommodation providers who did not always do the right thing," said the university in a statement.
At King's College London, campaign secretary "Juno" likewise reported hundreds of new pledges to withhold rent in the past few days, saying students felt they had been "lured" into their accommodation at the start of the academic year.
A King's spokesperson promised that students would not be charged for accommodation they are unable to use during lockdown.
About a quarter of students are in privately-run purpose built accommodation, and one of the biggest of these providers, Unite Students, is also facing demands.
Liverpool John Moores student Suhail Accad, in Unite accommodation, says his rent strike post on Instagram has gained 3,000 followers and has had 8,000 shares in just a few days.
"It's expensive to stay here," says Suhail.
Unite was unable to comment directly on the threat of rent strikes but maintains that it is doing all it can to help keep students and staff safe "during this challenging period".
Universities UK said universities were looking at the issue "actively" and considering what support they can offer students.
"Universities recognise the financial pressures the pandemic has placed on students and are providing increased financial and other support as a result.
"With government restrictions reducing the numbers of students returning in person to universities, now is the time for the government to seriously consider the financial implications for students and institutions and what support they will provide."