The University of Manchester is drawing up staff "research profiles", under which academics are given a score of between one and four for their research performance.
The rating will be decided by faculty assessment panels on the basis of an individual's external research grant income, publications, PhD student supervision and other data.
A university spokesman said the exercise "aims to create an accurate, up-to-date set of research profiles that will be of great value when it comes to developing future research priorities, informing funding decisions and preparing the university for the forthcoming research excellence framework".
He said staff could "check and correct the data, make comments about additional factors or extenuating circumstances and make a statement on impact".
In June, Times Higher Education reported that the University of Leeds was compiling "activity profiles" of all its academics in order to benchmark their research and teaching.
Members of the University and College Union at Manchester are following their colleagues at Leeds in opposing the latest plans.
The union is arguing that matters involving individual research - such as improved strategies for publication and grant applications - should be discussed through existing appraisal processes.
"Our members are incensed by this issue - both those who are the main targets of the research profiling exercise and those senior staff who sit on the assessment panels," a union spokesman said.
"It's fundamentally flawed in terms of accuracy and of the university's ability to maintain confidentiality."
Concerns have also been raised about the expertise of staff making the judgments.
A UCU briefing says: "The assessment will be done by a faculty panel with only one representative from each school, who will thus have little or no expertise in the subject area in most cases. No account will be taken of the variations in publication volume, citation rates etc across sub-disciplines."
The Manchester spokesman insisted that assessment would be conducted by large panels with cross-faculty representation, an external member with experience in assessment of research, and senior academic and administrative staff.