Books would be housed in five prefabricated buildings on the car park next to the Bill Robertson Library in Union St East, while partitions would be erected inside the library to allow those parts of it not undergoing refurbishment to continue to be used.
"It is going to be done in a similar way to the information services [central library] building, and that worked well," Mr MacKay said last week,The Bill Robertson library was built in the late 1970s for students at the former Dunedin College of Education, which merged with the university at the start of 2007.
It was also the main library for Otago Polytechnic students and continues to be so.
The library would be completely overhauled in a year-long project starting in the new year, Mr MacKay said.
The work would include extensive refurbishment and modernisation of the library's facilities, new lifts, a new stairwell, a new audiovisual room, more individual and group study spaces, and an upgrade of broadband facilities.
Much of the work involved deferred maintenance and bringing the building up to current building standards, he said.
That would include installing new sprinklers and fire-resistant partitions.
The cost would be split 50-50 between the university and a government grant received at the time of the merger.
Mr MacKay said there were initially plans to extend the library building and install student lounge and cafe areas similar to the facilities provided for health sciences students at the Hunter Centre on Great King St.
However, the cost was too great and the plans were downsized.
Extending the building was still an option for the future, he said.