University of Otago campus development division director David Perry said the new build, in Great King St, was originally due to be completed by the end of December.
That deadline has been pushed out to February or March because the contractor did not realise how complicated the process would be, he said.
The new building will house specialty and teaching clinics, a primary care unit, radiography and surgical suites.
''Once the construction is completed and the building is handed over to the university, it will take the dental school a few further weeks to get the new building operationally ready.''
The first semester starts on February 25.
Mr Perry said students would continue to train and work on patients who came in to the university's Walsh Building, until they moved into the new clinical services building.
Once the new building is completed, the Walsh building would be refurbished.
The refurbishment was expected to be completed by about mid-2020, and the old building would eventually be home to research laboratories, academic offices, student support services and teaching laboratories.
''The two buildings will be linked by an 1800sqm atrium, the heart of the facility, to be used by patients, students and staff.''
In total, there will be 214 new dental chairs, 64 more than the existing dental school.
The project is estimated to cost $130million.
Mr Perry said the refurbishment of Hayward College hall of residence was on track and due to be complete by the time students came back for the year.
The project included rebuilding all 162 rooms, adding extra rooms, and expanding the dining room and common space, as well as improving access for students with disabilities, carrying out seismic strengthening upgrades, and upgrading fire systems.
