Senior Aberdeen University managers have been accused of being "intimidatory and bullying" in their approach to lecturers' pay.
The university has refused to offer some 40 staff, who are members of the Educational Institute of Scotland, any annual pay rise because of their reluctance to move to new contracts.
A move to ballot on industrial action was agreed by members this week.
The dispute has been running for some two years and centres on the merger of the former Northern College of Education with the university. Many of the staff work in teacher training.
Marian Healy, EIS national officer for further and higher education, has written to Professor Duncan Rice, the university principal, to underline union anger at the apparent denial of the national 3.44 per cent pay rise.
The union views the decision "with dismay" and claims it runs counter to national agreements on the transfer of staff who have retained their FE (64) TUPE contracts after the merger.
Staff who are members of the University Lecturers' Association within the EIS say they are the only academics in Scotland without any award backdated to last August in their May pay packets.
Last year, they claim that the university held back 0.3 of the national pay award, only shelling out 3 per cent.
No university spokesman was available for comment.