Unions at the University of Sussex are angry that the institution has not disclosed the names of the companies it is speaking to about running its facilities management and catering services even though 235 staff face being moved on to private contracts.
In a statement, they describe the bidding process as "poorly considered and secretive" and call on the university to consult properly with staff about the move.
In May, members of the University and College Union, Unison and Unite held a series of protests against the plans, which they fear will mean staff being employed on different terms and conditions.
Rob French, branch chair at Sussex UCU, said: "There is no justification for keeping staff and students in the dark, especially when these plans mean that one in ten of the workforce would have a new employer.
"This entire process has been poorly considered and secretive from the outset. The university seems intent on steamrollering these plans through without any proper consultation or thought about the risks outsourcing poses."
A spokeswoman for Sussex said the institution was seeking an external partner to run the services "to ensure we continue to provide high-quality services to our staff and students as we grow as a university".
"We are following a proper and carefully managed procurement process in accordance with [European Union] procurement regulations. This is designed to identify the partner that best meets the needs of the university in the interests of all our staff and students," she said.
"We are following precisely the process and timescale as laid out in May 2012 when we first informed staff and unions of our plans.
"The unions are fully informed of the process that we are going through, and we continue to discuss our plans with them."
She added that the university was talking to potential bidders and that "this remains commercially confidential until a preferred supplier is identified".
In its communication to staff about the plans in May, the university pointed out that it already worked with a range of external providers to deliver services on campus, such as grounds maintenance and most of the cleaning and laundry services.
It also stated that staff would transfer to the new providers on their current terms and conditions, with the exception of future participation in university pension schemes.