Up to 100 jobs are to be axed at Aberystwyth University following a major restructuring of its biology department.
The university's Institute of Biological, Environmental and Rural Sciences is in deficit, and Aberystwyth's governing body has approved plans that make job losses inevitable.
Aberystwyth has begun a consultation with staff and has said that compulsory and voluntary redundancies may be necessary.
In a statement, Aberystwyth says: "The council has resolved to respond to the financial position, and full consultation will take place with the staff and the trade unions, which will meet all legal obligations."
Although the university told the University and College Union Wales that about 70 full-time posts would be cut, the union claimed that 100 jobs were at risk. It has called for the consultation period to be extended from 30 to 90 days because of the discrepancy in the figures.
Bethan Thomas, regional support official at UCU Wales, said it was "staggering" that a new business plan for the department had been approved in principle "without knowing exactly how many individuals would be affected".
"This isn't petty semantics or a legal technicality: this is about the livelihoods of more than 100 people and their families," she said.
"At best, the university is being incompetent; at worst, it is misleading staff, students, funders and the public."
UCU Wales claimed that the case for redundancies had not been made.
"The Welsh Assembly Government has backed (the institute) with substantial investment, running into tens of millions of pounds, yet the university maintains that job cuts are necessary to ensure the continuing success of the department," Ms Thomas added.
Meanwhile, the University of Edinburgh is in talks with Edinburgh College of Art over a proposed merger in an attempt to secure its future.
The two institutions have worked together for more than 60 years, and jointly established the Edinburgh School of Architecture and Landscape Architecture last year.