In 1913, a member of the Dunedin City Brigade invented a new system of street fire alarms. The Duplex system was a street fire alarm where, in the event of an emergency, a box on a lamppost would have its glass smashed by a member of the public. This would send a signal to a switchboard operator who would then send a fire appliance to the correct address as indicated by the signal sent. This was to be the main system in New Zealand for the next 50 years. Even as late as the 1970s, this system was still being in some towns.

By the time these alarms were installed, all major brigades in the country were completely motorised.