The longstanding Dunedin book sale at the top of the building will be moved downstairs at the end of the month. The upper floor will be refurbished and leased out.
Ms Duffy said the book sale would decrease in size, making it more easily curated.
''It will be more accessible for elderly people, and younger people with children,'' she said.
Leasing the space would provide a good income stream for the business and for the building, helping with strengthening work, Ms Duffy said.
In September 2016 the bookshop invested in a seismic upgrade from 14% to 34% of national building standards, and the bookshop plans to increase the building to at least 67% of the standards.