The bi-centenary of Captain James Cook's exploration of the South Pacific was celebrated by New Zealand amateurs from 1969-10-01 until 1970-12-31. NZ amateurs could use the ZM prefix in place of their usual ZL prefix. 

Information by Barry Kirkwood ZM1BN, printed on the rear of a ZM1BN/A Snares Island OC-068 DXpedition QSL (tnx JN6ZRM) QSL for a QSO on 1969-12-14.