Staff at Leeds University this week threatened to strike amid accusations that 100 administrators were informed "without warning" that their jobs had been downgraded.
The Leeds branch of the new University and College Union confirmed that it had entered into dispute with the university following an angry emergency union meeting on Monday during which academics and support staff called for immediate work-to-rule action.
The staff accused university managers of imposing the changes, implemented as part of the new national job evaluation scheme, without any negotiation.
Gavin Reid, president of the Leeds union, said: "Long-standing staff of the university, some with over 30 years' service, feel insulted and humiliated by this botched attempt to attach a ranking index number to the value of their roles."
He added: "I call on the university to withdraw its letters that breach the contracts of our members by downgrading large numbers of academic-related staff and to enter serious negotiations."
But Leeds denied allegations that it had failed to negotiate. A spokesperson said that, while the roles of 100 administrative staff had been revised downwards, a further 100 academics had been upgraded. The spokesperson added that nobody would lose pay as a result of the changes and that there had been no breach of contract.
Stephen Scott, pro vice-chancellor for staff, said: "We are proud of our new promotions and grading system, which we believe is fair, transparent and gives equality of opportunity to all staff.
"This has been a partnership - every stage of the process has been fully discussed and agreed with our unions. We will give every support to staff in assimilating to the new system."
The threat of action came as a national survey revealed that support staff in well over half of old universities are still waiting for their pay to be modernised, with just two months to go before the official deadline for the work to be completed.
But most of those institutions where job evaluations have been carried out under the pay framework agreement between unions and employers have seen a significant improvement in salaries, according to Amicus, which represents 15,000 support staff in higher education.
Out of 40 pre-92 institutions that the union surveyed, 55 per cent have yet to complete a job evaluation process and agree a formula for harmonising pay and conditions.
The survey revealed that in institutions where the framework agreement is in place up to 60 per cent of staff on some grades, such as technical and clerical, are better off under the new structures.
Amicus said it believed this was because many these grades included a high proportion of staff from "long-suffering discriminated against groups", such as women.
Mike Robinson, Amicus national secretary, said: "It is amazing just how undervalued many university staff members are.
"This survey has shown that job evaluation is not only necessary, it is a matter of justice to get equal pay for equal work."
He added that it was worrying that so many institutions had yet to complete pay harmonisation, with some indicating that they would not have the new arrangements in place until at least January next year.
Another concern was that many institutions had not committed to carrying out regular equal-pay audits to monitor the impact of changes under the framework agreement.
Mr Robinson said: "A lot of institutions have failed to fulfil their statutory obligation to introduce a monitoring process.
"They have either ignored the statutory requirements or they have been too busy doing other things to do the proper equal-opportunities monitoring."