More than 100 staff at the University of Salford have begun a four-day strike in support of two sacked colleagues.
The dispute is over the dismissal in December of two senior staff members in the university's marketing and student recruitment department.
They had previously expressed concerns about restructuring plans, said the University and College Union (UCU).
Staff began the strike with a picket line outside the main university building at about 07:00 BST.
The UCU claims the university denied the dismissed staff members the opportunity to appeal.
Regional official Martyn Moss said: "Staff at the university are fiercely determined in their support for their sacked colleagues. The university's behaviour has been totally unacceptable.
"The union remains committed to achieving a negotiated settlement through talks.'
The university said it was trying to resolve the matter with the pair and was disappointed by the strike.
A spokesman said: "We have been trying to resolve this dispute with the individuals concerned and are therefore disappointed further strike action has been called. We expect student activities to be unaffected by the action.
"We hope that a resolution can be found but, as this is an ongoing legal matter, we are unable to comment further."