Jobs are to be cut at Cardiff University as it moves to address a £21m deficit in its budget.
Vice-chancellor Colin Riordan wrote to all university staff on Friday saying applications for voluntary severance will open in the new year.
A statement from three trade unions said job losses had become "a reflex reaction rather than a last resort".
Cardiff University said it was a time of "unprecedented disruption and financial constraint".
It added the university had seen "substantial cuts" to its income from the Higher Education Funding Council for Wales (HEFCW) from £11m in 2017-18 to £6m for 2018-19.
In the letter from Mr Riordan to staff, he said the scheme for voluntary redundancies would be open from January to May.
He added the university was aiming for a £24m surplus in two years.
Cardiff University said there were "no specific plans for compulsory job losses", but they "cannot be ruled out".
The University and College Union, Unison and Unite said they were "astonished" Cardiff University was facing its "third voluntary severance scheme in six years" in a joint statement.
The unions added: "We are in this situation because of continued mismanagement at the highest level. Only last year we were told that the university's budget deficit was predicted and manageable, but now our jobs are on the line yet again.
"When a football manager performs this badly they either resign or get the sack, but Cardiff University managers seem to be immune from this kind of accountability. For them, laying off staff has become a reflex reaction, rather than an option of last resort.
"Morale among our members is already at rock bottom because of stagnating wages, unmanageable workloads, attacks on pensions, and continued investment in shiny new buildings instead of staff."
The university said: "The severance scheme is one of a number of responsible and prudent measures being undertaken or considered by the university to bring it back to surplus in 2019-20.
"We are and will be working with the trade unions to ensure that we have their input as proposals are developed, and once full proposals are agreed by council, they will be widely disseminated for meaningful consultation with all those involved.
"It's very important that any proposals we put forward in order to meet the challenges are robust, fair and workable."