The University of Bath says it will investigate how student accommodation on its campus was turned into offices.
Local councillors claim that planning rules have been ignored and the university did not obtain formal permission to make the changes.
A spokesman for the university says the inquiries will look at paperwork going back more than 20 years.
Last month Bath and North East Somerset Council announced it plans to impose restrictions on the amount of student housing in the city.
Cllr Will Sandry says despite the benefits of having a "world-class" university, it is important to address the housing issues facing Bath.