Hull University is facing industrial action this winter after announcing plans to make 110 out of a total of 142 cleaners redundant to cut costs.
A university spokeswoman said the move was regrettable but was part of a wider scheme to preserve core teaching and research activities. She said a 90-day consultation period was under way before the measures came into force and stressed that student houses would still be cleaned.
She said: "We have been requested by our governing council to reduce costs, partly because of declining overseas student income, and we wish to preserve our core activities. This will affect only university-owned student houses and not our halls of residence, all of which will still be cleaned regularly."
Steve Torrance, branch secretary of Unison, said the university had indicated that support staff were now expendable. He said: "This is a counter-productive move that has serious health and safety implications for students in campus residences.
"Students and parents expect university residences to be properly serviced, but it is clear the university now regards its accommodation as a capital asset that needs to make profit."
Mr Torrance added: "The cleaners are low-paid women and just as much part of the education team as anyone else. We have to win this battle and will take whatever measures are necessary."
He said that he had seen documents suggesting that the university was planning to ask students to take on more janitorial duties in university houses. He said this was bound to have a detrimental effect on admissions.
The university spokeswoman said no decisions had been made about future arrangements and more extensive discussions with students were planned for the new term.