The maintenance of adequate children's libraries is part of the accepted responsibility of public libraries. It is, however, in school libraries that many children first encounter a selection of what becomes to some the exciting world of books. School libraries for many years were confined to a few of the larger post-primary schools. In many cases their maintenance was – and still is – the devoted responsibility of the English department. Sometimes special bequests and donations add to the range of choice. In recent years the need has become apparent for broadly based collections, interesting and attractive in themselves and useful as an adjunct to the work of all departments. While accommodation and stock have greatly improved, particularly in some new schools, the library has frequently been ignored in the competition for funds, and establishment grants have not been adequate. So far, too, there has been no official recognition of the need for trained teacher-librarians. While some teachers' colleges have been able to give trainees an opportunity of seeing what can be done with books, the current crisis in post-primary staffing has had its effect on such work.

The Dunedin Public Library, in conjunction with the Otago Education Board, in 1938 commenced a service to city and country schools which other boards have attempted to follow. Increasingly, however, the School Library Service has in part compensated for the inadequacies of local development. Originating in 1942 as a section of the Country Library Service, it became a separate division of the National Library Service in 1949. Bulk exchanges of books are provided to all primary, intermediate, and district high schools. A request service is also available through which individual titles can be borrowed both by these schools and by post-primary schools. For the year 1961–62, £95,500 was provided for book purchases by the School Library Service.

Although 1,738,752 books were supplied to schools in 1964, the number of books available within any one school is necessarily limited. The Service also gives valuable assistance by the compilation of lists of books for purchasing and for borrowing, a comprehensive series of graded lists having been maintained for some years.