The university started telling its 2000-plus general staff members about the proposed cutbacks last month.
More recently, it set up a space on the university website for students and staff to read about the review and make submissions on it.
Tertiary Education Union (TEU) organiser Shaun Scott said the university's open call for submissions on the review was unusual, probably because the review itself was unusually broad.
''This is a totally new approach from university management. Certainly, for years and years, they've not embarked on something this wide-ranging.''
Staff were cautious about contributing to the consultation process, ''because of concerns about the work that will remain at the university, and how jobs might be structured in the future''.
''It's an ongoing level of concern for people,'' he said.
But human resources director Kevin Seales said the university's wide-ranging move was far from unprecedented.
''The university has consulted with staff many times in the past when changes have been proposed ... When the university is looking at changing its activities that might affect students, they are consulted.''
So far, the university had received 107 submissions from the website form, he said.
Documents published on the website show the university is planning to complete the ''research and scoping'' phase of the review by early 2016, and that Otago is 19% ''more administratively resourced than the benchmark''.
Mr Scott said he did not think that meant staff numbers would be reduced by 19% - or more than 400 full-time employees - but there were definitely some staff who were concerned that it did.
Mr Seales would not confirm or deny whether cuts in staffing would reach the 19% figure, saying only there was ''no set target for reduction in staffing or savings to be made''.
''Until the scope is determined and solutions are designed ... it is not possible to determine the impact of any resulting change.''
Also among the published documents is a graph with the number of full-time equivalent general staff (FTEs) and equivalent full-time students (efts) over time.
The graph shows efts peaking in 2010, then falling steadily, while FTEs were growing steadily over time.
It also shows that, in 2006, there was a bigger difference between general staff numbers and student numbers than there is now.
But Mr Seales said the difference was acceptable in 2006 because student numbers were trending upwards.
Now that they were trending down, there needed to be ''a corresponding decrease in general staff FTEs''.
The same document cites ''ongoing efts and funding concerns'' as a primary reason for the review.
Mr Scott said staff were also worried about the effect a reduction in general staffing might have on the quality of university services.
PSA organiser Keith McFadyen said, like TEU members, PSA's Otago members were ''anxious and worried'' about the review.
