A poor road surface and old equipment could be causing the traffic lights at West End to continually break down, according to the New Zealand Transport Agency.
The West End traffic lights, at the corner of Malfroy and Old Taupo Rds (State Highway 5), went out again on the weekend, only a few days after their last outage.
Rotorua police said they had the same problem last week, with officers being sent to monitor the intersection.
Transport Agency Bay of Plenty Highways manager Niclas Johansson said the signals were due for an upgrade.
"The poor condition of the asphalt at the intersection of State Highway 5 and Malfroy Rd, as well as the age and condition of the signal wiring, is contributing to the problem of traffic lights faulting," he said.