Ms Dell, addressing well-wishers, said marked the "memorable and special day" by reading an extract from the library's founder, Dr Thomas Hocken.
Dr Hocken, who was unable to attend the 1910 opening because of illness, sent a speech in which he said: "This work has been to me a labour of love and in it I have put into practice a sentiment I have always held: that it is the bounden duty of every citizen to do something for his state in the welfare of which his own happiness and prosperity are very largely found."
Former Hocken librarian Stuart Strachan told the Otago Daily Times the library housed the most important collection outside Crown ownership in New Zealand.
"It's one of the institutions that helps lend Dunedin and the University [of Otago] national distinction."
Dr Hocken offered his collection, which included books, manuscripts, newspapers, and maps, to the city in 1897; several years, and a public subscription drive later, a special wing was added to the Otago Museum.
The collection is now housed in the former Otago Dairy Co-operative in Anzac Ave.
