The Royal New Zealand Navy Long Service and Good Conduct Medal was instituted in 1985 to replace the Royal Navy Long Service and Good Conduct Medal, with eligibility being backdated to 1 December 1977. It is awarded to naval ratings up to and including the rank of Warrant Officer who have completed 15 years unblemished service.

Non-commissioned RNZN personnel who completed their military service prior to 1 December 1977 required 15 years' service to be awarded the Royal Navy Long Service and Good Conduct Medal. Personnel who completed their military service on or after 1 December 1977 require 15 years' unblemished service to be awarded the Royal New Zealand Navy Force Long Service and Good Conduct Medal.