The Tertiary Education Union is upset it cannot get secret benchmarking data that compares polytechnics with one another.
The union says the information is being used to justify attacks on staff conditions but it cannot get the details because the polytechnics say it is commercially sensitive.
Manukau Institute of Technology is now about to use the figures to review all its departments.
The union says it may be the first time a polytechnic has used the information for such a large-scale review.
The union is worried polytechnics will endanger the quality of their teaching if they try to be more efficient than one another, based on the benchmarking data.
But polytechnics say the figures are only an indicator and will not drive institutions to copy one another exactly.
