The functions of the Society are local, national, and international.

Local responsibilities are met by the activities of regional branches in supporting museums, libraries, or observatories, holding meetings for delivery of lectures, and maintaining a watching brief over matters of scientific interest locally. Branches in the larger centres take turns in organising the triennial Science Congress of the Royal Society of New Zealand.

National responsibilities include the publication of the Society's Transactions, in four series since 1961 (General, Zoology, Botany, Geology), and of Bulletins, major works too large for inclusion in the Transactions. The library of the Rcyal Society of New Zealand, built up by exchange, consists of some 30,000 volumes, with an annual increment of 1,500 items. It contains many valuable long runs of scientific periodicals and constitutes a bibliographic tool for all New Zealand research workers, available through interloan.

High standards in research are encouraged by the election of New Zealand scientists of high achievement to the fellowship of the Royal Society of New Zealand, a statutory and honorary recognition of distinction for life which entitles the fellows (limited to 100) to use the letters F.R.S.N.Z.