The cameras cost $4000 each and the $72,000 funding for the project is being met by the New Zealand Transport Agency.
Acting state highway manager for the Bay of Plenty, Adam Francis, said the new system was part of the agency's ongoing renewal programme for Rotorua.
"The purpose of the traffic cameras is to help ensure that the signals are used most effectively to assist with the safe and efficient movement of traffic."
He said the traffic cameras were becoming standard in larger cities in New Zealand and around the world and they provided a visual confirmation for those managing the network of what was happening on the ground - all aimed at managing outages, congestion and the sequencing of signals.
The live feed from the cameras is monitored by the Tauranga Traffic Operations Centre, where staff are able to detect faults or traffic issues and address them early on.
As part of the renewal programme, the 18 sets of traffic lights are also being upgraded. Rotorua has historically had issues with traffic lights, with some of the problems in the past being blamed on geothermal activity.
Bay of Plenty police road policing manager Inspector Kevin Taylor said it was hoped the new traffic lights would alleviate dangerous situations at intersections where traffic lights had stopped working.
"It's supposed to revert to the right hand rule but often at times it reverts to law of the jungle. One driver thinks 'I am going first because I am in a bigger hurry than you', or another thinks 'I am bigger than you so I will push my way in'."
He said the new monitoring of intersections was also welcomed.
"It will give them better information for decisions around sequencing of traffic lights and anything that helps reduce congestion and gets people moving has got to be a good thing."
A Rotorua Lakes Council spokesman said the agency would provide access to the cameras when needed as part of its partnership with the council and Rotorua police.
Traffic lights with new cameras
* Fenton and Hinemoa Streets
* Fairy Springs, Lake and Clayton Rds
* Old Taupo and Sunset Rds
* Old Taupo Rd and Pukuatua St
* Old Taupo and Malfroy Rds