Mount Maunganui ward councillor Steve Morris (pictured below) said it was especially frustrating when there were two drivers travelling side by side on both lanes at slow speeds.
"Obviously people are still feeling comfortable at peak-hour traffic driving 70 to 80km/h, causing frustration," Mr Morris said.
The frustration resulted in people sometimes speeding in an effort to pass the slower vehicles, he said.
"It's not just one or two.
"You've got quite a stream of traffic driving at 30 kilometres below the speed limit.
"When you've got them driving like that in both lanes, I just can't understand it."
Mr Morris' comments come after a man was arrested for allegedly speeding at 200km/h on the new road.
Mr Morris said while he had not witnessed such an extreme case himself, he had seen drivers speed in effort to get in front of slow drivers.
Fellow councillor Leanne Brown, who lives in Papamoa, said it seemed there were two extremes "which will hopefully balance out as drivers become more familiar with the new route".
"It's fantastic that it's opening in stages and the new stretch certainly speeds up travel time and will hopefully take pressure off the congested Papamoa Beach Rd at peak times".
NZ Transport Agency's Bay of Plenty highways manager Niclas Johansson said there were signs advertising the 100km/h limit at Te Maunga and Domain Rd intersection.
"When a new road opens it can take people time to get used to the changes and some motorists may choose to drive at speeds under the posted limit for a variety of reasons," Mr Johansson said.
"On this 6km stretch of the expressway there are four lanes, two in each direction, allowing drivers to overtake motorists travelling at slower speeds. We encourage those drivers choosing to travel at slower speeds to keep the left-hand lane."
Mr Johansson said it was important to remember the speed limit was the maximum legal speed to travel at - not a minimum travel speed, nor a target.
